![]() To better understand the regulation of Tat stability, we adopted a new proteomics approach (DiffPOP) designed to identify drug-protein targets based on their differential solubility in the presence of the drug. Here, we have investigated a small molecule compound, JIB-04, which induces the rapid and selective destruction of the HIV-1 Tat protein in HeLa and T cells, with minimal effects on host cell transcription. The HIV-1 Tat protein is critical for virus expression and replication, but little is known about the factors that control its expression level in T cells. We conclude that HIV-1 Tat levels are regulated through K63Ub-selective autophagy mediated through SHMT1,2 and the BRCC36 deubiquitinase. Moreover, point mutation of multiple lysines in Tat, or knockdown of BRCC36 or SHMT1,2, was sufficient to prevent destruction of Tat by JIB-04. Importantly, knockdown of SHMT1,2 or BRCC36, or exposure of cells to JIB-04, strongly increased Tat K63Ub-dependent destruction via autophagy. Mass-spectrometry analysis of whole-cell extracts from 2D10 Jurkat T cells revealed that JIB-04 targets Serine Hydroxymethyltransferase 2 (SHMT2), a regulator of glycine biosynthesis and an adaptor for the BRCC36 K63Ub-specific deubiquitinase in the BRISC complex. Here we use a novel proteomics technique, called DiffPOP, to identify the molecular target of JIB-04, a small molecule compound that potently and selectively blocks HIV-1 Tat expression, transactivation, and virus replication in T cell lines. HIV-1 Tat is a key regulator of viral transcription, however little is known about the mechanisms that control its turnover in T cells. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
March 2023
Categories |