Non-viral cellular substrates for human immunodeficiency virus type 1 protease

A Computer search revealed 10 proteins with homology to the sequence we originally identified in vimentin as the site of cleavage by human immunodeficiency virus type 1 (HIV-1) protease. Of these 10 proteins (actin, α-actinin, spectrin, tropomyosins, vinculin, dystrophin, MAP-2, villin, TRK-1 and lg μ-chain), we show that 4 of the first 5 were cleaved in vitro by this protease, as arc MAP-1 and -2 [(1990) J. Gen. Virol. 71, 1985–1991]. In these proteins, cleavage is not restricted to a single motif, but occurs at many sites. However, cleavage is not random, since 9 other proteins including the cytoskeletal proteins filamin and band 4.1 are not cleaved in the in vitro assay. Thus, the ability of HIV-1 protease to cleave specific components or the cytoskeleton may be an important, although as yet unevaluated aspect of the life cycle of this retrovirus and/or may directly contribute to the pathogenesis observed during infection.