Thursday, May 21, 2020

ABHD17 enzymes regulate dynamic plasma membrane palmitoylation and N-Ras-dependent cancer growth [@MJNiphakis]

Jarrett R Remsberg, Radu M Suciu, Noemi A Zambetti, Thomas W Hanigan, Ari J Firestone, Anagha Inguva, Amy Long, Nhi Ngo, Kenneth M Lum, Cassandra L Henry, Stewart K Richardson, Marina Predovic, Ben Huang, Amy R Howell, Micah J Niphakis, Kevin Shannon, Benjamin F Cravatt
bioRxiv, 2020

A subset of Ras proteins, including N-Ras, depend on a palmitoylation/depalmitoylation cycle to regulate their subcellular trafficking and oncogenicity. General lipase inhibitors such as Palmostatin M block N-Ras depalmitoylation, but lack specificity and target several enzymes displaying depalmitoylase activity. Here, we describe ABD957, a potent and selective covalent inhibitor of the ABHD17 family of depalmitoylases, and show that this compound impairs N-Ras depalmitoylation in human acute myeloid leukemia (AML) cells. ABD957 produced partial effects on N-Ras palmitoylation compared to Palmostatin M, but was much more selective across the proteome, reflecting a plasma membrane-delineated action on dynamically palmitoylated proteins. Finally, ABD957 impaired N-Ras signaling and the growth of NRAS-mutant AML cells in a manner that synergizes with MEK inhibition. Our findings uncover a surprisingly restricted role for ABHD17 enzymes in modulating the N-Ras palmitoylation cycle and suggest that ABHD17 inhibitors may have value as targeted therapies for NRAS-mutant cancers


Chemical Specification of E3 Ubiquitin Ligase Engagement by Cysteine-Reactive Chemistry

Roman C. Sarott, Inchul You, Yen-Der Li, Sean T. Toenjes, Katherine A. Donovan, Pooreum Seo, Martha Ordonez, Woong Sub Byun, Muhammad Murtaz...