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

Area of Science:

• Virology
• Cell Biology
• Biochemistry

Background:

• The human immunodeficiency virus type 1 (HIV-1) protease is essential for viral maturation.
• Cytoskeletal proteins play critical roles in cell structure and function.
• Previous studies identified a cleavage site in vimentin by HIV-1 protease.

Purpose of the Study:

• To investigate whether HIV-1 protease cleaves other cytoskeletal proteins.
• To identify specific cytoskeletal targets of HIV-1 protease.
• To explore the potential implications of this cleavage in viral pathogenesis.

Main Methods:

• Computer-based homology search for potential protein targets.
• In vitro cleavage assays using purified HIV-1 protease and various cytoskeletal proteins.
• Analysis of cleavage sites within susceptible proteins.

Main Results:

• Ten proteins with homology to the vimentin cleavage site were identified.
• Four of the first five homologous proteins (actin, alpha-actinin, spectrin, tropomyosins, vinculin) were cleaved in vitro.
• MAP-1 and MAP-2 were also shown to be cleaved, with multiple cleavage sites observed.
• Cleavage was specific, as filamin and band 4.1 were not cleaved.

Conclusions:

• HIV-1 protease exhibits specific cleavage activity against several cytoskeletal proteins.
• The cleavage is not limited to a single motif but occurs at multiple sites.
• This protease-mediated cytoskeletal disruption could be a significant factor in HIV-1 replication and disease progression.