RT Journal Article
SR Electronic
T1 Lipid Raft-Independent B Cell Receptor-Mediated Antigen Internalization and Intracellular Trafficking
JF The Journal of Immunology
JO J. Immunol.
FD American Association of Immunologists
SP 905
OP 912
DO 10.4049/jimmunol.170.2.905
VO 170
IS 2
A1 Putnam, Michelle A.
A1 Moquin, Amy E.
A1 Merrihew, Megan
A1 Outcalt, Christopher
A1 Sorge, Emily
A1 Caballero, Adriana
A1 Gondré-Lewis, Timothy A.
A1 Drake, James R.
YR 2003
UL http://www.jimmunol.org/content/170/2/905.abstract
AB The Ag-specific B cell receptor (BCR) expressed by B lymphocytes has two distinct functions upon interaction with cognate Ag: signal transduction (generation of intracellular second messenger molecules) and Ag internalization for subsequent processing and presentation. While it is known that plasma membrane domains, termed lipid rafts, are involved in BCR-mediated signal transduction, the precise role of plasma membrane lipid rafts in BCR-mediated Ag internalization and intracellular trafficking is presently unclear. Using a highly characterized model system, it was determined that while plasma membrane lipid rafts can be internalized by B lymphocytes, lipid rafts do not represent a major pathway for the rapid and efficient internalization of cell surface Ag-BCR complexes. Moreover, internalized plasma membrane lipid rafts are delivered to intracellular compartments distinct from those to which the bulk of internalized Ag-BCR complexes are delivered. These results demonstrate that B lymphocytes, like other cell types, possess at least two distinct endocytic pathways (i.e., clathrin-coated pits and plasma membrane lipid rafts) that deliver internalized ligands to distinct intracellular compartments. Furthermore, Ag-BCR complexes differentially access these two distinct internalization pathways.