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The Journal of Immunology, 1998, 160: 1547-1551.
Copyright © 1998 by The American Association of Immunologists

CUTTING EDGE

Cutting Edge: Lyn-Mediated Down-Regulation of B Cell Antigen Receptor Signaling: Inhibition of Protein Kinase C Activation by Lyn in a Kinase-Independent Fashion

Hitoshi Katsuta*,{dagger}, Sachiyo Tsuji*, Yoshiyuki Niho{dagger}, Tomohiro Kurosaki{ddagger} and Daisuke Kitamura1,*

* Division of Molecular Biology, Research Institute for Biological Sciences, Science University of Tokyo, Chiba, Japan; {dagger} First Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan; and {ddagger} Department of Molecular Genetics, Institute for Liver Research, Kansai Medical University, Moriguchi, Japan


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results and Discussion
 References
 
Stimulation of the B cell Ag receptor (BCR) induces activation of tyrosine kinases such as Lyn and Syk, phosphorylation and activation of multiple signaling components, and eventually, the expression of several genes including c-myc. Syk is required for activation of phospholipase C-{gamma}2 and the subsequent phosphatidylinositol hydrolysis, leading to protein kinase C (PKC) activation and intracellular Ca2+ increase. In contrast, the function of Lyn remains obscure. Here, we report that BCR-mediated induction of c-myc promoter activity and of PKC activity, but not the expression level of functional PKC, was markedly augmented in Lyn-deficient chicken B cells. This enhancement was reversed to the level of wild-type cells by the expression of exogenous Lyn of kinase-inactive form. These results indicate that Lyn inhibits BCR-mediated activation of a large portion of PKC isozymes in a kinase-independent fashion. This finding reveals a novel role of Lyn in negative regulation of BCR signaling.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results and Discussion
 References
 
The B cell Ag receptor (BCR)2 complex is composed of membrane Ig and Ig{alpha}/Igß heterodimers. Cross-linking of the BCR rapidly induces activation of protein tyrosine kinases (PTKs) including Src-family kinases, Lyn, Fyn, Blk, as well as Syk and Btk kinases, resulting in tyrosine phosphorylation of a number of membrane and cytoplasmic proteins, including the kinases mentioned above, Ig{alpha}/Igß and phospholipase C-{gamma}2 (PLC-{gamma}2) (reviewed in Refs. 1 and 2). It is proposed that the Src-family kinases first phosphorylate Ig{alpha}/Igß, to which Syk binds through its Src homology 2 (SH2) domains, and then Syk is phosphorylated by Src-family kinases. This phosphorylation, together with a conformational change upon this binding, has been proposed to activate Syk (3, 4, 5, 6).

One target of activated Syk is PLC-{gamma}2 (7). Phosphorylated PLC-{gamma}2 becomes active and causes phosphatidylinositol (PI) hydrolysis, generating inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). IP3 releases Ca2+ from intracellular stores through binding to its receptor (8), while DAG binds to and activates a major part of protein kinase C (PKC) isozymes (9). PKC isozymes are divided into three groups: conventional PKC (cPKC), which is dependent on Ca2+ and DAG; novel PKC (nPKC), dependent on DAG but not on Ca2+; and atypical PKC (aPKC), which is dependent on neither Ca2+ nor DAG. Any of these PKC isozymes may also require certain phospholipids such as phosphatidylserine (PS) or PI. The function of DAG can be taken over artificially by phorbol esters such as PMA (reviewed in 9 . Previous studies have shown that, in B cells, cross-linking of BCR as well as treatment with PMA induces rapid activation of PKC, a translocation of the PKC from cytosol to plasma membrane (10, 11), and also the expression of a variety of genes such as c-myc, c-fos, and egr-1 (12, 13, 14). However, the isozyme(s) activated upon BCR stimulation, which may be responsible for the induction of these genes, has largely been unknown. Recently, it has been reported that one isozyme, PKCµ, was activated upon BCR cross-linking (15), and also that PKCß-deficient mice showed impaired humoral immune responses and proliferative responses of B cells (16). These findings strongly suggest that some PKC isozymes are functionally important in BCR signaling.

One of the authors (T.K.) has previously established chicken DT40 B cell lines rendered deficient for Syk, Lyn, Btk, or PLC-{gamma}2 by targeted mutagenesis. Studies performed with these cell lines showed that PLC-{gamma}2 is indispensable for BCR-mediated PI hydrolysis and the subsequent biochemical events including PKC activation (17, 18). Syk and Btk are required for phosphorylation of PLC-{gamma}2 and manifestation of PLC-{gamma}2 activity (7, 19). Lyn has been shown to phosphorylate and activate Syk and Btk (2, 3). In the Lyn-deficient cells, BCR-induced tyrosine phosphorylation of cellular proteins is markedly reduced, while PI hydrolysis is not impaired (7), leaving the role of Lyn unclarified.

Our aim was to understand the mechanism that links the early events aforementioned to the induction of gene expression in BCR signaling. Toward this end, utilizing these mutant lines, we first sought to clarify a requirement of PTKs for the induction of the c-myc gene, which plays a crucial role in cell proliferation as well as apoptosis. As reported here, we have found a novel role of Lyn in negative regulation of BCR signaling.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results and Discussion
 References
 
Plasmid construction

To construct c-myc-Luc, a luciferase reporter vector driven by enhancer/promoter region of the c-myc gene, a 4-kb KpnI-XhoI fragment including a 5' flanking region and an exon I of mouse c-myc gene (20), and an XhoI-BamHI fragment containing a promoterless luciferase gene from the PicaGene basic vector-2 (Toyo Inki, Tokyo, Japan) were coligated with a KpnI-BamHI fragment from pUC18. Pactßgal containing Escherichia coli lacZ gene driven by chicken ß-actin promoter was a gift of T. Yagi (21). pME-Lyn (22) and pME-LynKL were gifts from H. Nishizumi (Institute of Medical Science, The University of Tokyo, Tokyo, Japan). In pME-LynKL, Lys-275 (codon AAA) in an ATP-binding site of Lyn was replaced by Leu (codon TTA) by means of site-directed mutagenesis (23) using a cDNA insert of pME-Lyn as a template.

DNA transfection and cell stimulation

Syk-, Lyn-, and PLC-{gamma}2-deficient cell lines were generated from DT40 chicken B cell lines and maintained as described previously (7, 17). These cells were electroporated with circular plasmid DNAs using Gene Pulser apparatus (Bio-Rad Laboratories, Hercules, CA). Briefly, 5 x 106 cells with 22 µg (or 20 µg, shown in Fig. 3Go) DNA in 0.25 ml of RPMI medium (FCS free) per cuvette were pulsed at 250 V, 975 µF; then, cells from cuvettes were collected and cultured at 2 x 105/ml for 48 h. Then, the cells were divided and stimulated as described in the figure legends at 2 x 106 cells/2 ml culture medium for each stimulation, unless otherwise noted. Anti-chicken IgM mAb M4 (a gift of C.-L. Chen (24)), PMA (Wako, Osaka, Japan) and ionomycin (Wako) were used for the stimulation. When noted, cells were incubated for 1 h before stimulation with 10 µM PKC-specific inhibitor GF109203X (Calbiochem, San Diego, CA).



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  		FIGURE 3. Lyn down-regulates PKC activation by BCR cross-linking or by PMA. Wild-type (WT) and Lyn-deficient (Lyn-) DT40 cells (1.5 x 107 each) were transfected with 60 µg pME18S, respectively, or the latter, with 60 µg pME-LynKL. After 48 h, 107 cells in 10 ml of culture medium were left untreated (-) or treated with 15 µg/ml anti-IgM or 100 ng/ml PMA for 10 min; then, the cells were collected and lysed. Cell lysates containing equal amounts of protein were subjected to in vitro kinase assay with a MARCKS peptide as a PKC-specific substrate. The samples were fractionated by 15% SDS-PAGE and visualized by autoradiography. Detailed procedures are described in Materials and Methods. a, Indicates that PS, PMA, and Ca2+ were added (+) or not (-) in vitro in the assay.

 
Luciferase assay

After washing with PBS, 2 x 106 cells were lysed with 200 µl of lysis buffer, and 20 µl aliquots of each lysate were measured for luciferase activity with a kit (PicaGene luciferase assay system, Toyo Inki) and for ß-galactosidase activity with a kit (Galacto-Light; Tropix, Inc., Bedford, MT) as described in the suppliers’ instructions. Chemiluminescence was measured using a Lumat LB9501 luminometer (Berthold Japan, Tokyo, Japan). Luciferase activity was normalized to ß-galactosidase activity.

In vitro PKC assay

After appropriate stimulation, cells were harvested and solubilized in digitonin lysis buffer (1% digitonin, 50 mM Tris, pH6.7, 150 mM NaCl, 2 mM EDTA, 2 mM Na3VO4, 10 mM NaF, 20 µg/ml leupeptin, 33 µg/ml aprotinin, 1 mM PMSF). Protein concentrations in the detergent-soluble lysates were determined using the bicinchoninic acid assay (Pierce, Rockford, IL) and adjusted to 1 mg/ml by dilution with the lysis buffer. The lysates were diluted eightfold with a kinase buffer (40 mM PIPES, pH7.0, 10 mM MgCl2, and 10 mM MnCl2 (15)). Then, 5.5 µl of each diluted sample was incubated at 30°C for 15 min in the kinase buffer (10 µl final) with 10 µCi of [{gamma}-32P]ATP and 100 nM MARCKS peptide (Lys151-Lys175 (25); Biomol Research Laboratories, Plymouth Meeting, PA) as a substrate, in the absence or presence of the following activators: 280 µg/ml phosphatidylserine (Sigma, St. Louis, MO), 10 µM PMA, and 1 mM CaCl2 (26). The reactions were terminated by boiling in SDS sample buffer, and the samples were analyzed by 15% SDS-PAGE. After electrophoresis, the gels were dried on Whatman paper and exposed to autoradiography film. Quantitation was achieved by exposure to a phosphor screen and analyzed using the MolecularImager (Bio-Rad).


   Results and Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results and Discussion
References
 
BCR-mediated activation of c-myc promoter is dependent of Syk and PLC-{gamma}2

To clarify the role of PTKs in the BCR-mediated signaling pathway leading to induction of gene expression, DT40 chicken B cell line and mutant lines lacking Lyn, Syk, or PLC-{gamma}2 (7, 17) were transfected with a reporter construct containing luciferase gene driven by c-myc promoter. The luciferase activity was measured after BCR cross-linking by anti-IgM Ab or after treatment with PMA and/or ionomycin, as controls (Fig. 1Go). BCR cross-linking of the wild-type cells induced the reporter gene expression, which reached a maximum of ~10-fold enhancement (Fig. 1GoA). PMA-treated cells showed a higher degree of induction, with similar kinetics, which was further increased in the presence of ionomycin that alone failed to induce the reporter gene expression (Fig. 1GoA, data not shown). Thus, PMA-responsive PKCs (cPKC and nPKC) are likely to be involved in the BCR-mediated activation of the c-myc promoter. The additive effect of ionomycin further suggests the involvement of a cPKC isozyme, namely PKC{alpha}, which requires an elevated intracellular Ca2+ for full activity, or the complementary role of calcium-dependent factors, such as calcineurin.



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  		FIGURE 1. Activation of c-myc promoter upon BCR cross-linking is abrogated in Syk- or PLC-{gamma}2-deficient, but augmented in Lyn-deficient, chicken DT40 B cell lines. DT40 and the mutant cells (2 x 107 each) were cotransfected with 80 µg c-myc-Luc reporter and 8 µg pactßgal standard plasmids. After 48 h, the cells were divided and stimulated with nothing (none), 15 µg/ml anti-IgM, or 100 ng/ml PMA, either alone or in combination with of 1 µM ionomycin (Iono) for the indicated lengths of time. Lysates from these cells were subjected to luciferase and ß-galactosidase assays. Detailed procedures are described in Materials and Methods. The relative luciferase activity for each sample was normalized with the ß-galactosidase activity, and mean values with SDs of the normalized activities obtained from an experiment performed in triplicate are shown.

 
In Syk- or PLC-{gamma}2-deficient DT40 cells, BCR-mediated activation of the c-myc promoter was completely abolished, indicating that activation of PLC-{gamma}2 by Syk and the subsequent generation of DAG, or IP3, or both, is required for this induction (Fig. 1Go, C and D). This result suggests that a transcription factor(s) activated by PKC and/or an increased intracellular Ca2+ is responsible for the BCR-mediated activation of c-myc promoter. PMA or PMA + ionomycin treatment of the Syk- or PLC-{gamma}2-deficient cells showed a degree and kinetics of reporter activity almost identical to that observed after the same treatment of wild-type DT40 cells. This finding indicates that these reagents act on molecules downstream of Syk and PLC-{gamma}2 in the signaling pathway leading to c-myc promoter activation (Fig. 1Go, C and D).

Lyn down-regulates activation of c-myc promoter by BCR cross-linking or by PMA

In striking contrast to Syk- or PLC-{gamma}2-deficient cells, Lyn-deficient cells showed an augmented response of the c-myc promoter activity to anti-IgM stimulation (Fig. 1GoB). Thus, when compared with wild-type cells, a nearly threefold increased activity was evident throughout the time course of anti-IgM treatment of the Lyn-deficient cells. Unexpectedly, a similar enhancement was observed also after PMA stimulation of the same cells. This result was surprising because PMA directly activates PKC located downstream of the BCR-associated PTKs in the BCR signal cascade. The additive effect of ionomycin to PMA was only moderately augmented by the absence of Lyn.

To clarify whether the lack of Lyn is a primary cause for the enhanced response to anti-IgM and PMA in Lyn-deficient cells, Lyn expression vector was cotransfected with the reporter construct into the cells. As shown in Figure 2Go, expression of the exogenous Lyn suppressed the reporter activity induced by anti-IgM as well as PMA in Lyn-deficient cells to a level similar to that observed in wild-type cells. Surprisingly, a similar vector carrying a kinase-inactive form of Lyn (LynKL) could also inhibit the induction. These results indicate that Lyn is directly involved in the down-regulation of the BCR-mediated signal and that a PKC-mediated pathway is a likely target of Lyn in this signal down-regulation. This function of Lyn does not require its kinase activity, and it seems to be achieved by the physical association with other molecule(s).



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  		FIGURE 2. Lyn down-regulates activation of c-myc promoter by BCR cross-linking or by PMA. Wild-type and Lyn-deficient (Lyn-) DT40 cells (5 x 106 each) were cotransfected with 10 µg c-myc-Luc and 2 µg pactßgal plasmids with either 10 µg empty vector pME18S (for wild-type and Lyn-deficient cells), 10 µg pME-Lyn, or 10 µg pME-LynKL (for Lyn-deficient cells). After 48 h, some cells were stimulated with 15 µg/ml anti-IgM or 100 ng/ml PMA. After 3, 6, and 12 h, stimulated and unstimulated control cells were lysed and subjected to luciferase and ß-galactosidase assays. Detailed procedures are described in Materials and Methods. The luciferase activity for each sample was normalized with the ß-galactosidase activity. Bars represent the means with SDs of the fold induction values over those recorded for the unstimulated controls; data are obtained from an experiment performed in triplicate.

 
Lyn down-regulates PKC-activation by BCR cross-linking or by PMA

In view of the results described above, we then examined whether Lyn directly inhibits the activation of PKC. PKC activities in the whole cell lysates before and after stimulation were measured by in vitro kinase assay using a PKC-specific peptide substrate derived from MARCKS protein (25). As shown in Figure 3Go (upper panel), PKC activity was induced by anti-IgM and more strongly by PMA in the wild-type cells. Strikingly, the level of PKC activities was markedly elevated in Lyn-deficient cells (3.5- or 3.3-fold by anti-IgM or PMA, respectively, the level in wild-type cells, as analyzed by phosphor-imaging). This elevation in Lyn-deficient cells was completely reversed by the transfection of the kinase-inactive LynKL vector, indicating a kinase-independent inhibition of PKC activity by Lyn. Pretreatment of these cells with a PKC-specific inhibitor, GF109203X (27), completely abrogated the in vitro kinase activity induced by anti-IgM or PMA stimulation, confirming the specificity of the substrate (data not shown). When these lysates were subjected to the same assay but with the addition of PKC activators PS, PMA and Ca2+ in vitro, which together should activate most of the PKC isozymes (9), the PKC activities in those lysates were almost identical, indicating that a similar amount of functional PKC was present in those lysates (Fig. 3Go, lower panel). Together, these results strongly suggest that Lyn inhibits the activation of a large portion of PKC isozymes induced by anti-IgM or PMA, without affecting the expression level of functional PKC. This inhibitory function of Lyn is independent of its kinase activity.

These findings also indicate that PKC, the activation of which was inhibited by Lyn in vivo, could be activated upon addition of the activators in vitro despite the presence of Lyn. This suggests that Lyn does not modify PKC into a nonfunctional form nor constitutively bind to PKC to block its binding sites for these activators. Since after stimulation PKC translocates to the plasma membrane where Lyn is located, the translocated PKC might be prevented by Lyn from gaining access to some physiological activator at the membrane.

Recently, a negative regulatory role for Lyn in BCR signaling has been observed in B cells from young Lyn-deficient mice (28, 29). BCR cross-linking on these B cells led to an enhanced proliferative response and a greater activation of MAP kinase (MAPK) pathway compared with wild-type B cells. It has been proposed that negative regulatory coreceptors such as CD22 and Fc{gamma}RIIB may be involved in this phenomenon. Both molecules were previously shown to down-regulate BCR-signal when cross-linked with BCR (30, 31, 32). CD22 and Fc{gamma}RIIB are tyrosine phosphorylated in their cytoplasmic domains upon cross-linking, and recruit SH2-containing protein tyrosine phosphatase SHP-1, and SH2-containing inositol polyphosphate 5'-phosphatase SHIP, respectively, which are presumed to dephosphorylate key signaling proteins and lipids in BCR signaling (32, 33, 34, 35, 36, 37, 38). Hyper-responsive phenotypes commonly observed in CD22-, Fc{gamma}RIIB-, SHP-1-, SHIP-, and Lyn-deficient B cells have led to the assumption that Lyn may be critical for the phosphorylation of CD22 and Fc{gamma}RIIB (38, 39, 40, 41, 42, 43, 44). However, our present data indicate that Lyn may down-regulate BCR signaling in a different way, directly inhibiting PKC activation in a kinase-independent fashion. This novel role of Lyn would explain the hyperactivation of MAPK pathway, despite a delayed tyrosine phosphorylation observed in BCR-stimulated B cells from Lyn-deficient mice (29), since some PKC isozymes have been shown to directly activate the MAPK pathway (45, 46). In light of the appearance of autoantibodies and autoimmune disease in Lyn-deficient mice (29, 47, 48), the inhibitory role of Lyn in BCR signaling appears to be critical for setting a proper threshold on B cells so that they may not respond to environmental cross-reacting Ags.


   Acknowledgments
 
The authors thank Drs. H. Nishizumi, Y. Yamanashi, and T. Yamamoto for pME-Lyn and pME-LynKL; T. Yagi for pactßgal; C.-L. Chen and M. Cooper for mAb M4; and F. P. Zavala for critical reading of the manuscript.


   Footnotes
 
1 Dr. Daisuke Kitamura, Division of Molecular Biology, Research Institute for Biological Sciences, Science University of Tokyo, Yamazaki 2669, Noda-city, Chiba 278, Japan. E-mail address: Back

2 Abbreviations used in this paper: BCR, B cell Ag receptor; PTK, protein tyrosine kinase; PLC-{gamma}2, phospholipase C-{gamma}2; PI, phosphatidylinositol; IP3, inositol 1,4,5-trisphosphate; DAG, diacylglycerol; PKC, protein kinase C; MARCKS, myristoylated alanine-rich C kinase substrate; PS, phosphatidylserine; cPKC, conventional PKC; nPKC, novel PKC; SH2, Src homology 2; LynKL, kinase-inactive form of Lyn. Back

Received for publication November 10, 1997. Accepted for publication November 24, 1997.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results and Discussion
 References
 

  1. DeFranco, A. L.. 1997. The complexity of signaling pathways activated by the BCR. Curr. Opin. Immunol. 9:296.[Medline]
  2. Kurosaki, T.. 1997. Molecular mechanisms in B cell antigen receptor signaling. Curr. Opin. Immunol. 9:309.[Medline]
  3. Kurosaki, T., M. Takata, Y. Yamanashi, T. Inazu, T. Taniguchi, T. Yamamoto, H. Yamamura. 1994. Syk activation by the Src-family tyrosine kinase in the B cell receptor signaling. J. Exp. Med. 179:1725.[Abstract/Free Full Text]
  4. Kurosaki, T., S. A. Johnson, L. Pao, K. Sada, H. Yamamura, J. C. Cambier. 1995. Role of the Syk autophosphorylation site and SH2 domains in B cell antigen receptor signaling. J. Exp. Med. 182:1815.[Abstract/Free Full Text]
  5. Johnson, S. A., C. M. Pleiman, L. Pao, J. Schneringer, K. Hippen, J. C. Cambier. 1995. Phosphorylated immunoreceptor signaling motifs (ITAMs) exhibit unique abilities to bind and activate Lyn and Syk tyrosine kinases. J. Immunol. 155:4596.[Abstract]
  6. Rowley, R. B., A. L. Burkhardt, H. G. Chao, G. R. Matsueda, J. B. Bolen. 1995. Syk protein-tyrosine kinase is regulated by tyrosine-phosphorylated Ig{alpha}/Igß immunoreceptor tyrosine activation motif binding and autophosphorylation. J. Biol. Chem. 270:11590.[Abstract/Free Full Text]
  7. Takata, M., H. Sabe, A. Hata, T. Inazu, Y. Homma, T. Nukada, H. Yamamura, T. Kurosaki. 1994. Tyrosine kinases Lyn and Syk regulate B cell receptor-coupled Ca2+ mobilization through distinct pathways. EMBO J. 13:1341.[Medline]
  8. Berridge, M. J.. 1993. Inositol trisphosphate and calcium signalling. Nature 361:315.[Medline]
  9. Nishizuka, Y.. 1992. Intracellular signaling by hydrolysis of phospholipids and activation of protein kinase C. Science 258:607.[Abstract/Free Full Text]
  10. Chen, Z. Z., K. M. Coggeshall, J. C. Cambier. 1986. Translocation of protein kinase C during membrane immunoglobulin-mediated transmembrane signaling in B lymphocytes. J. Immunol. 136:2300.[Abstract]
  11. Nel, A. E., M. W. Wooten, G. E. Landreth, P. J. Goldschimdt-Clermont, H. C. Stevenson, P. J. Miller, R. M. Galbraith. 1986. Translocation of phospholipid/Ca2+-dependent protein kinase in B-lymphocytes activated by phorbol ester or cross-linking of membrane immunoglobulin. Biochem. J. 233:145.[Medline]
  12. Kelly, K., B. H. Cochran, C. D. Stiles., P. Leder. 1983. Cell-specific regulation of the c-myc gene by lymphocyte mitogens and platelet-derived growth factor. Cell 35:603.[Medline]
  13. Monroe, J. G.. 1988. Up-regulation of c-fos expression is a component of the mIg signal transduction mechanism but is not indicative of competence for proliferation. J. Immunol. 140:1454.[Abstract]
  14. Seyfert, V. L., S. McMahon, W. Glenn, X. Cao, V. P. Sukhatme, J. G. Monroe. 1990. Egr-1 expression in surface Ig-mediated B cell activation. Kinetics and association with protein kinase C activation. J. Immunol. 145:3647.[Abstract]
  15. Sidorenko, S. P., C. L. Law, S. J. Klaus, K. A. Chandran, M. Takata, T. Kurosaki, E. A. Clark. 1996. Protein kinase C µ (PKCµ) associates with the B cell antigen receptor complex and regulates lymphocyte signaling. Immunity 5:353.[Medline]
  16. Leitges, M., C. Schmedt, R. Guinamard, J. Davoust, S. Schaal, S. Stabel, A. Tarakhovsky. 1996. Immunodeficiency in protein kinase Cß-deficient mice. Science 273:788.[Abstract]
  17. Takata, M., Y. Homma, T. Kurosaki. 1995. Requirement of phospholipase C-{gamma} 2 activation in surface immunoglobulin M-induced B cell apoptosis. J. Exp. Med. 182:907.[Abstract/Free Full Text]
  18. Sugawara, H., M. Kurosaki, M. Takata, T. Kurosaki. 1997. Genetic evidence for involvement of type 1, type 2 and type 3 inositol 1,4,5-trisphosphate receptors in signal transduction through the B-cell antigen receptor. EMBO J. 16:3078.[Medline]
  19. Takata, M., T. Kurosaki. 1996. A role for Bruton’s tyrosine kinase in B cell antigen receptor-mediated activation of phospholipase C-{gamma} 2. J. Exp. Med. 184:31.[Abstract/Free Full Text]
  20. Yang, J.-Q., E. F. Remmers, K. B. Marcu. 1986. The first exon of the c-myc proto-oncogene contains a novel positive control element. EMBO J. 5:3553.[Medline]
  21. Yagi, T., Y. Shigetani, N. Okado, T. Tokunaga, Y. Ikawa, S. Aizawa. 1993. Regional localization of Fyn in adult brain: studies with mice in which fyn gene was replaced by lacZ. Oncogene 8:3343.[Medline]
  22. Yamanashi, Y., T. Fukuda, H. Nishizumi, T. Inazu, K. Higashi, D. Kitamura, T. Ishida, H. Yamamura, T. Watanabe, T. Yamamoto. 1997. Role of tyrosine phosphorylation of HS1 in B cell antigen receptor-mediated apoptosis. J. Exp. Med. 185:1387.[Abstract/Free Full Text]
  23. Kunkel, T. A.. 1985. Rapid and efficient site-specific mutagenesis without phenotypic selection. Proc. Natl. Acad. Sci. USA 82:488.[Abstract/Free Full Text]
  24. Chen, C.-L., J. E. Lehmeyer, M. D. Cooper. 1982. Evidence for an IgD homologue on chicken lymphocytes. J. Immunol. 129:2580.[Abstract]
  25. Graff. J. M., R. R., R. R. Rajan, A. C. Randall, A. C. Nairn, P. J. Blackshear. 1991. Protein kinase C substrate and inhibitor characteristics of peptides derived from the myristoylated alanine-rich C kinase substrate (MARCKS) protein phosphorylation site domain. J. Biol. Chem. 266:14390.[Abstract/Free Full Text]
  26. Baier-Bitterlich, G., F. Uberall, B. Bauer, F. Fresser, H. Wachter, H. Grunicke, G. Utermann, A. Altman, G. Baier. 1996. Protein kinase C-{theta} isoenzyme selective stimulation of the transcription factor complex AP-1 in T lymphocytes. Mol. Cell. Biol. 16:1842.[Abstract]
  27. Toullec, D., P. Pianetti, H. Coste, P. Bellevergue, T. Grand-Perret, M. Ajakane, V. Baudet, P. Boissin, E. Boursier, F. Loriolle, L. Duhamel, D. Charon, J. Kirilovsky. 1991. The bisindolylmaleimide GF 109203X is a potent and selective inhibitor of protein kinase C. J. Biol. Chem. 266:15771.[Abstract/Free Full Text]
  28. Wang, J., T. Koizumi, T. Watanabe. 1996. Altered antigen receptor signaling and impaired Fas-mediated apoptosis of B cells in Lyn-deficient mice. J. Exp. Med. 184:831.[Abstract/Free Full Text]
  29. Chan, V. W., F. Meng, P. Soriano, A. L. DeFranco, C. A. Lowell. 1997. Characterization of the B lymphocyte populations in Lyn-deficient mice and the role of Lyn in signal initiation and down-regulation. Immunity 7:69.[Medline]
  30. Phillips, N. E., D. C. Parker. 1984. Cross-linking of B lymphocyte Fc{gamma} receptors and membrane immunoglobulin inhibits anti-immunoglobulin-induced blastogenesis. J. Immunol. 132:627.[Abstract]
  31. Amigorena, S., C. Bonnerot, J. R. Drake, D. Choquet, W. Hunziker, J. G. Guillet, P. Webster, C. Sautes, I. Mellman, W. H. Fridman. 1992. Cytoplasmic domain heterogeneity and functions of IgG Fc receptors in B lymphocytes. Science 256:1808.[Abstract/Free Full Text]
  32. Doody, G. M., L. B. Justement, C. C. Delibrias, R. J. Matthews, J. Lin, M. L. Thomas, D. T. Fearon. 1995. A role in B cell activation for CD22 and the protein tyrosine phosphatase SHP. Science 269:242.[Abstract/Free Full Text]
  33. Muta, T., T. Kurosaki, Z. Misulovin, M. Sanchez, M. C. Nussenzweig, J. V. Ravetch. 1994. A 13-amino-acid motif in the cytoplasmic domain of Fc{gamma}RIIB modulates B-cell receptor signalling. Nature 368:70.[Medline]
  34. D’Ambrosio, D., K. H. Hippen, S. A. Minskoff, I. Mellman, G. Pani, K. A. Siminovitch, J. C. Cambier. 1995. Recruitment and activation of PTP1C in negative regulation of antigen receptor signaling by Fc{gamma}RIIB1. Science 268:293.[Abstract/Free Full Text]
  35. Campbell, M. A., N. R. Klinman. 1995. Phosphotyrosine-dependent association between CD22 and protein tyrosine phosphatase 1C. Eur. J. Immunol. 25:1573.[Medline]
  36. Law, C.-L., S. P. Sidorenko, K. A. Chandran, Z. Zhao, S.-H. Shen, E. H. Fischer, E. A. Clark. 1996. CD22 associates with protein tyrosine phosphatase 1C, Syk, and phospholipase C-{gamma}1 upon B cell activation. J. Exp. Med. 183:547.[Abstract/Free Full Text]
  37. Ono, M., S. Bolland, P. Tempst, J. V. Ravetch. 1996. Role of the inositol phosphatase SHIP in negative regulation of the immune system by the receptor Fc{gamma}RIIB. Nature. 383:263.[Medline]
  38. Ono, M., H. Okada, S. Bolland, S. Yanagi, T. Kurosaki, J. V. Ravetch. 1997. Deletion of SHIP or SHP-1 reveals two distinct pathways for inhibitory signaling. Cell 90:293.[Medline]
  39. O’Keefe, T. L., G. T. Williams, S. L. Davies, M. S. Neuberger. 1996. Hyperresponsive B cells in CD22-deficient mice. Science 274:798.[Abstract/Free Full Text]
  40. Otipoby, K. L., K. B. Andersson, K. E. Draves, S. J. Klaus, A. G. Farr, J. D. Kerner, R. M. Perlmutter, C.-L. Law, E. A. Clark. 1996. CD22 regulates thymus-independent responses and the lifespan of B cells. Nature 384:634.[Medline]
  41. Sato, S., A. S. Miller, M. Inaoki, C. B. Bock, P. J. Jansen, M. L. K. Tang, T. F. Tedder. 1996. CD22 is both a positive and negative regulator of B lymphocyte antigen receptor signal transduction: altered signaling in CD22-deficient mice. Immunity 5:551.[Medline]
  42. Nitschke, L., R. Carsetti, B. Ocker, G. Kohler, M. C. Lamers. 1997. CD22 is a negative regulator of B-cell receptor signalling. Curr. Biol. 7:133.[Medline]
  43. Takai, T., M. Ono, M. Hikida, H. Ohmori, J. V. Ravetch. 1996. Augmented humoral and anaphylactic responses in Fc{gamma}RII-deficient mice. Nature 379:346.[Medline]
  44. Cyster, J. G., C. C. Goodnow. 1995. Protein tyrosine phosphatase 1C negatively regulates antigen receptor signaling in B lymphocytes and determines thresholds for negative selection. Immunity 2:13.[Medline]
  45. Van Renterghem, B., M. D. Browning, J. L. Maller. 1994. Regulation of mitogen-activated protein kinase activation by protein kinases A and C in a cell- free system. J. Biol. Chem. 269:24666.[Abstract/Free Full Text]
  46. Ueda, Y., S. Hirai, S. Osada, A. Suzuki, K. Mizuno, S. Ohno. 1996. Protein kinase C {delta} activates the MEK-ERK pathway in a manner independent of Ras and dependent on Raf. J. Biol. Chem. 271:23512.[Abstract/Free Full Text]
  47. Hibbs, M. L., D. M. Tarlinton, J. Armes, D. Grail, G. Hodgson, R. Maglitto, S. A. Stacker, A. R. Dunn. 1995. Multiple defects in the immune system of Lyn-deficient mice, culminating in autoimmune disease. Cell 83:301.[Medline]
  48. Nishizumi, H., I. Taniuchi, Y. Yamanashi, D. Kitamura, D. Ilic, S. Mori, T. Watanabe, T. Yamamoto. 1995. Impaired proliferation of peripheral B cells and indication of autoimmune disease in lyn-deficient mice. Immunity 3:549.[Medline]



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