| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Microbiology, Michigan State University, East Lansing, MI 48824
CD45 contains tandem repeated protein tyrosine phosphatase (PTP) domains and is essential for the initiation of the earliest activation events resulting from Ag ligation of the TCR. The second PTP domain (D2) contains four CK2 phosphorylation sites in a unique 19-aa insert, which are targets of CK2 phosphorylation. This study was designed to evaluate the roles of these Ser residues in T cell activation. Transient transfection of the CD45- T cell line, J45.01, with CD45 cDNA incorporating four Ser to Ala (S/A) mutations in the 19-aa insert did not affect the magnitude of NF-AT activation resulting from TCR ligation. However, the basal level of NF-AT activity in unstimulated cells expressing the CD45 S/A mutation was elevated 9- to 10-fold. Increased basal NF-AT was dependent on extracellular Ca2+ stores as judged by EGTA treatment. In additional experiments, isolation of stable clones derived from transfection of the CD45 S/A mutant into CD45- H45.01 cells showed sustained calcium flux after TCR engagement. The sustained calcium flux returned to baseline levels after addition of EGTA, suggesting that the expression of the CD45 S/A mutant may have prevented deactivation of plasma membrane calcium channels. Consideration of both transient and stable transfection systems suggests that in addition to being essential for initial events in T cell triggering, the intact CD45 D2, 19-aa insert is necessary for regulation of TCR-mediated calcium signaling pathways.
This article has been cited by other articles:
|
|
 |
|
  P. Contini, M. Ghio, A. Merlo, A. Poggi, F. Indiveri, and F. Puppo Apoptosis of Antigen-Specific T Lymphocytes upon the Engagement of CD8 by Soluble HLA Class I Molecules Is Fas Ligand/Fas Mediated: Evidence for the Involvement of p56lck, Calcium Calmodulin Kinase II, and Calcium-Independent Protein Kinase C Signaling Pathways and for NF-{kappa}B and NF-AT Nuclear Translocation J. Immunol., December 1, 2005; 175(11): 7244 - 7254. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Wang and P. Johnson Expression of CD45 Lacking the Catalytic Protein Tyrosine Phosphatase Domain Modulates Lck Phosphorylation and T Cell Activation J. Biol. Chem., April 8, 2005; 280(14): 14318 - 14324. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. A. Robichaud, B. Barbeau, J.-F. Fortin, D. M. Rothstein, and M. J. Tremblay Nuclear Factor of Activated T Cells Is a Driving Force for Preferential Productive HIV-1 Infection of CD45RO-expressing CD4+ T Cells J. Biol. Chem., June 21, 2002; 277(26): 23733 - 23741. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Wu, J. Fu, and S.-H. Shen SKAP55 Coupled with CD45 Positively Regulates T-Cell Receptor-Mediated Gene Transcription Mol. Cell. Biol., April 15, 2002; 22(8): 2673 - 2686. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Barbeau, G. A. Robichaud, J.-F. Fortin, and M. J. Tremblay Negative Regulation of the NFAT1 Factor by CD45: Implication in HIV-1 Long Terminal Repeat Activation J. Immunol., September 1, 2001; 167(5): 2700 - 2713. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. F. Greer, Y.-n. Wang, C. Raman, and L. B. Justement CD45 Function Is Regulated by an Acidic 19-Amino Acid Insert in Domain II That Serves as a Binding and Phosphoacceptor Site for Casein Kinase 2 J. Immunol., June 15, 2001; 166(12): 7208 - 7218. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
