Identification of Helicase Proteins as Clients for HSP90.

ABSTRACT: The 90-kDa heat shock protein (HSP90) is a molecular chaperone that maintains the proper folding of its client proteins including protein kinases and steroid hormone receptors. Helicases are a group of nucleic acid-binding ATPases that can unwind DNA and/or RNA and function in almost every aspect of nucleic acid metabolism. Not much, however, is known about the interactions between HSP90 and helicase proteins. Herein, we developed a parallel-reaction monitoring (PRM)-based targeted proteomic method that allows for quantifying >80% of the human helicase proteome. By employing this method, we demonstrated that a large number of helicase proteins exhibited diminished expression in cultured human cells upon treatment with two small-molecule inhibitors of HSP90. We further introduced a tandem affinity tag to the C-terminus of endogenous HSP90? protein by using the CRISPR-Cas9 genome editing method. Affinity purification followed by LC-PRM analysis revealed an enrichment of 40 out of the 66 quantified helicases from the lysate of cells expressing tagged HSP90?. Together, we developed a high-throughput targeted proteomic method for assessing quantitatively the human helicase proteome, and our results support that helicases may constitute an important group of client proteins for HSP90.

SUBMITTER: Miao W 

PROVIDER: S-EPMC6434711 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature