Blockade of human immunodeficiency virus type 1 expression by caveolin-1.
Caveolin-1 (Cav-1) is a major protein constituent of caveolae, a type of plasma membrane raft. We observed that coexpression of human Cav-1 with human immunodeficiency virus type 1 (HIV-1) blocked virion production from cells that are ordinarily highly permissive. Further investigation showed that this effect is specific, occurs at low ratios of Cav-1 to HIV-1 DNA, depends on expression of Cav-1 protein, and involves severely impaired expression of HIV-1 proteins. Cav-1 also blocked HIV-2 expression. In contrast, Cav-1 did not inhibit protein expression by a paramyxovirus and did not induce apoptosis or affect cellular morphology, cell viability, or cell cycle progression. Although only small amounts of HIV-1 virions were released from Cav-1-transfected cells, these were fully infectious. Deletion mutagenesis showed that the C-terminal 78 residues were as active as the full-length (178-amino-acid) protein in producing the block. In contrast, the 100 most N-terminal amino acids of Cav-1, which include the previously identified oligomerization and scaffolding domains, were shown to be dispensable. Study of single-amino-acid-exchange mutants of Cav-1 established that palmitoylation was not required. Additional deletion mutants then identified the hydrophobic, membrane-associated domain (residues 101 to 135) as the main determinant. Cellular distribution of wild-type and mutant proteins correlated with ability to block HIV-1 expression. Finally, Cav-2 also blocked HIV-1 expression. These data show that coexpression of caveolins can markedly inhibit expression of HIV proviral DNA and establish that the inhibition is mediated by the hydrophobic, membrane-associated domain.
Molecular Medicine Program and Departments of Immunology, Mayo Clinic, Rochester, Minnesota 55905, USA.
Manuel
M
Llano
Tara
T
Kelly
Maria
M
Vanegas
Mary
M
Peretz
Timothy E
TE
Peterson
Robert D
RD
Simari
Eric M
EM
Poeschla
D051242:Caveolin 1; D022461:Caveolins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003673:Defective Viruses; D005455:Fluorescent Antibody Technique; D017353:Gene Deletion; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D015498:HIV-2 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D011533:Proviruses / Q000235:genetics / Q000378:metabolism; D018108:Respirovirus / Q000378:metabolism; D014162:Transfection; D014764:Viral Proteins / Q000187:drug effects / Q000378:metabolism; D014771:Virion / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*
C495540:CAV1 protein, human; D051242:Caveolin 1; D022461:Caveolins; D014764:Viral Proteins