Proteomic study of the mechanism of talin-C as an inhibitor of HIV infection

Talin-1 is involved in human immunodeficiency virus (HIV) invasion and synapse development. We found that talin-1 was cleaved into a 38 KDa fragment (talin-C) in the peripheral blood mononuclear cells (PBMCs) of HIV patients; however, the underlying mechanisms remain unknown. This study aimed to determine the relationship between talin-C and HIV infection and identify the mechanisms underlying the ability of this protein to influence HIV infection. PBMCs were derived from HIV-infected patients enrolled in this study. N- and C-terminal peptides matching the potential sequence of talin-C were detected in PBMCs by multiple reaction monitoring (MRM) mass spectrometry. TZM-b1 cells were infected with HIV-1 pseudotyped virus (HIVpp) for different durations to detect the talin-C product. Three stable cell lines overexpressing talin head (TLN1-H) or TLN1-C or with TLN1 knockdown (shTLN1) were created and infected by HIVpp. The HIV marker protein (P24) was then detected by enzyme-linked immunosorbent assay. Finally, an isobaric tag for relative and absolute quantification (iTRAQ)-based proteomic study was performed to detect the TLN1-C-regulated proteins with or without HIVpp infection in TZM-bl cells. The identified proteins were analyzed by R version 4.0.2, and STRING software (Version: 11.0) (https://string-db.org). N- and C-peptides of talin-C were detected to have higher expression in patients with lower HIV load. Talin-C was produced during HIVpp infection. TLN1-C significantly inhibited HIVpp infection in the TZM-b1 cells. Additionally, a proteomic study found that TLN1-C regulated the expression of 99 proteins in TZM-b1 cells without and with HIVpp infection, respectively. According to Gene Ontology (GO) annotation, proteins with cellular metabolic process and binding function were found to be enriched. Thirty four proteins have protein-protein interaction, including 19 down- and 15 up- regulated proteins, respectively. Talin-C was produced following HIV infection, and is inversely proportional to HIV load. A proteomic study indicated that TLN1-C might be involved in HIV infection through regulating metabolic processes.