%0 Journal Article
%A Reche Gallardo, Pedro Antonio
%A Reinherz, Ellis L
%A Moody, A M
%A Chui, D
%A Priatel, J J
%A Marth, J D
%T Developmentally regulated glycosylation of the CD8alphabeta coreceptor stalk modulates ligand binding.
%D 2001
%@ 0092-8674
%U https://hdl.handle.net/20.500.14352/58251
%X The functional consequences of glycan structural changes associated with cellular differentiation are ill defined. Herein, we investigate the role of glycan adducts to the O-glycosylated polypeptide stalk tethering the CD8alphabeta coreceptor to the thymocyte surface. We show that immature CD4(+)CD8(+) double-positive thymocytes bind MHCI tetramers more avidly than mature CD8 single-positive thymocytes, and that this differential binding is governed by developmentally programmed O-glycan modification controlled by the ST3Gal-I sialyltransferase. ST3Gal-I induction and attendant core 1 sialic acid addition to CD8beta on mature thymocytes decreases CD8alphabeta-MHCI avidity by altering CD8alphabeta domain-domain association and/or orientation. Hence, glycans on the CD8beta stalk appear to modulate the ability of the distal binding surface of the dimeric CD8 globular head domains to clamp MHCI.
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