Alterations in CD45 glycosylation pattern accompanying different cell proliferation states

CD45 is a leukocyte-specific transmembrane glycoprotein whose intracellular domain exhibits protein tyrosine phosphatase activity and plays a critical role in signal transduction. CD45 derived from stationary lymphocytes migrated faster in SDS-PAGE than that derived from exponentially growing cells. A change in N-linked saccharide structure other than the neuraminidase-sensitive terminal sialic acid portion was found to be responsible for the molecular size change in CD45. The differential glycosylation appeared to occur during late-stage posttranslational processing of CD45. We speculate that the N-glycosylation difference affects the interaction between CD45 and other factors involved in signal transduction leading to modulation of leukocyte proliferation.