Association ofp56Ick withthecytoplasmic domainof CD4modulates HIV-1expression

precisely within thefirst immunoglobulin-like domain termed D1 (Landauet al., 1988; Mizukami et al., 1988; Peterson and Seed,1988; Arthos et al., 1989; Fleury et al., 1991). Thecyto-plasmic domainofCD4is notrequiredforHIV-1 entry intocells since infection wasshownto occurdespitethedeletionofthewholedomain(Bedingeret al., 1988; Maddonet al.,1988). The objective of these studies was to clarify theprecise role played by the cytoplasmic domain ofCD4inthe process of