Targeted genetic and small molecule disruption of N-Ras CaaX cleavage alters its localization and oncogenic potential

In this study, uncleavable sequences were used to stage Ras isoforms in a farnesylated and uncleaved state to address the impact of CaaX proteolysis on protein localization and function. This targeted strategy is more specific than those that chemically inhibit the Rce1 CaaX protease or delete the RCE1 gene because global abrogation of CaaX proteolysis impacts the entire CaaX protein proteome and effects cannot be attributed to any specific CaaX protein of the many concurrently affected. With this targeted strategy, clear mislocalization and reduced activity of farnesylated and uncleaved Ras isoforms was observed. In addition, new peptidomimetics based on cleavable Ras CaaX sequences and the uncleavable CAHQ sequence were synthesized and tested as Rce1 inhibitors using in vitro and cell-based assays. Consistently, these non-hydrolyzable peptidomimetic Rce1 inhibitors recapitulate Ras mislocalization effects when modeled on cleavable but not uncleavable CaaX sequences. These findings indicate that a prenylated and uncleavable CaaX sequence, which can be easily applied to a wide range of mammalian CaaX proteins, can be used to probe the specific impact of CaaX proteolysis on CaaX protein properties under conditions of an otherwise normally processed CaaX protein proteome.PMID:38583246 | DOI:10.1016/j.bioorg.2024.107316

Source: Bioorganic Chemistry - April 7, 2024 Category: Chemistry Authors: Emily R Hildebrandt Shaneela A Hussain Michelle A Sieburg Rajani Ravishankar Nadeem Asad Sangram Gore Takahiro Ito James L Hougland Timothy M Dore Walter K Schmidt Source Type: research