Post-translational Regulation of FNIP1 Creates a Rheostat for the Molecular Chaperone Hsp90.

ABSTRACT: The molecular chaperone Hsp90 stabilizes and activates client proteins. Co-chaperones and post-translational modifications tightly regulate Hsp90 function and consequently lead to activation of clients. However, it is unclear whether this process occurs abruptly or gradually in the cellular context. We show that casein kinase-2 phosphorylation of the co-chaperone folliculin-interacting protein 1 (FNIP1) on priming serine-938 and subsequent relay phosphorylation on serine-939, 941, 946, and 948 promotes its gradual interaction with Hsp90. This leads to incremental inhibition of Hsp90 ATPase activity and gradual activation of both kinase and non-kinase clients. We further demonstrate that serine/threonine protein phosphatase 5 (PP5) dephosphorylates FNIP1, allowing the addition of O-GlcNAc (

SUBMITTER: Sager RA 

PROVIDER: S-EPMC6370319 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature