Polar redistribution of the sialoglycoprotein CD43: implications for T cell function.
Contact between T cells and APCs results in the orchestrated segregation of molecules at the cell-cell interface and formation of a specialized structure termed the immunological synapse. This model predicts the topological seclusion of large molecules such as CD43 from the site of closest contact between the T cell and APC, allowing for the close apposition of cell membranes and effective TCR engagement. Similarly, during T cell migration segregation of CD43 to the uropod is thought to aid integrin adhesion at the leading edge of the cell by removing steric hindrance. We show in this work that CD43 distribution on T cells is regulated by a membrane proximal ezrin binding site and that failure to displace CD43 from the immunological synapse has no inhibitory effects on primary T cell activation. We also report that CD43 expression at the contact zone between T cells and matrix does not negatively regulate motility but may regulate LFA-1 de-adhesion. These results suggest that the steric barrier model of CD43 is inadequate and that alternative mechanisms account for the negative regulatory properties of CD43.
Savage
Nigel D L
ND
Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
Kimzey
Stephanie L
SL
Bromley
Shannon K
SK
Johnson
Kenneth G
KG
Dustin
Michael L
ML
Green
Jonathan M
JM
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology / Q000378:metabolism; D015703:Antigens, CD / Q000378:metabolism*; D002448:Cell Adhesion / Q000276:immunology; D002450:Cell Communication / Q000276:immunology*; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism; D002464:Cell Migration Inhibition; D002465:Cell Movement / Q000276:immunology; D016764:Cell Polarity / Q000276:immunology; D003593:Cytoplasm / Q000276:immunology / Q000378:metabolism; D051917:Leukosialin; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D008822:Mice, Transgenic; D017434:Protein Structure, Tertiary; D012795:Sialoglycoproteins / Q000378:metabolism*; D016176:T-Lymphocyte Subsets / Q000276:immunology*
D015703:Antigens, CD; D051917:Leukosialin; D012795:Sialoglycoproteins; C497863:Spn protein, mouse