The differential interactomes of the KRAS splice variants identify BIRC6 as a ubiquitin ligase for KRAS4A
Transcripts of the KRAS locus are alternatively spliced to generate two proteins, KRAS4A and KRAS4B, which differ in their membrane-targeting sequences. These splice variants have been conserved for more than 450 million years, suggesting non-overlapping functions driven by differential membrane association. Here, we use proximity labeling to map the differential interactomes of the KRAS splice variants. We find 24 and 10 proteins that interact specifically with KRAS4A or KRAS4B, respectively. The KRAS interacting protein most specific to KRAS4A is BIRC6, a large member of the inhibitor of apoptosis protein family unique in possessing E2/E3 ubiquitin ligase activity. We find that this interaction takes place on the Golgi apparatus and results in the mono- and di-ubiquitination of KRAS4A at lysines 128 and 147. Silencing BIRC6 diminishes GTP loading of and growth stimulation by KRAS4A but not KRAS4B. Thus, BIRC6 is a ubiquitin ligase that inhibits apoptosis and also modifies KRAS4A.
Authors
- Eric S. Fischer (ORCID: https://orcid.org/0000-0001-7337-6306)
- Mercedes Fissore-O'Leary
- Wenjuan Su (ORCID: https://orcid.org/0000-0002-2398-5100)
- Beatrix Ueberheide (ORCID: https://orcid.org/0000-0003-2512-0204)
- Moritz Hunkeler (ORCID: https://orcid.org/0000-0003-0246-1188)
- Ian M. Ahearn (ORCID: https://orcid.org/0000-0002-2275-137X)
- Cristina Branco (ORCID: https://orcid.org/0000-0001-6953-4922)
- Mark R. Philips (ORCID: https://orcid.org/0000-0002-1179-8156)
- Anna M. Schmoker (ORCID: https://orcid.org/0000-0003-2830-5650)
- Dominic Esposito (ORCID: https://orcid.org/0000-0002-9987-1687)
- Juan Andres Kochen Rossi (ORCID: https://orcid.org/0000-0001-6452-0249)
- Cristina Nuevo‐Tapioles (ORCID: https://orcid.org/0000-0001-5809-2030)
- Rachel A. O’Keefe (ORCID: https://orcid.org/0000-0003-3231-9772)
- Hakyung Cheong
- Ioana Clotea
Institutions
- Dana-Farber Cancer Institute (US)
- Frederick National Laboratory for Cancer Research (US)
- NYU Langone’s Laura and Isaac Perlmutter Cancer Center
- New York University (US)
Publication Details
- Journal
- Cell Reports
- Published
- 2024-12-19
- DOI
- https://doi.org/10.1016/j.celrep.2024.115087
- Citations
- 3
- Primary Topic
- Ubiquitin and proteasome pathways
- Type
- article
- Field-Weighted Citation Impact
- 0.70
Funders
- Astellas Pharma US
- Fundación Ramón Areces
- Astellas Pharma
- National Institutes of Health
- NYU Grossman School of Medicine
- National Cancer Institute