The C2 domain augments Ras GTPase-activating protein catalytic activity
Regulation of Ras GTPases by GTPase-activating proteins (GAPs) is essential for their normal signaling. Nine of the ten GAPs for Ras contain a C2 domain immediately proximal to their canonical GAP domain, and in RasGAP (p120GAP, p120RasGAP; <i>RASA1</i>) mutation of this domain is associated with vascular malformations in humans. Here, we show that the C2 domain of RasGAP is required for full catalytic activity toward Ras. Analyses of the RasGAP C2-GAP crystal structure, AlphaFold models, and sequence conservation reveal direct C2 domain interaction with the Ras allosteric lobe. This is achieved by an evolutionarily conserved surface centered around RasGAP residue R707, point mutation of which impairs the catalytic advantage conferred by the C2 domain in vitro. In mice, <i>R707C</i> mutation phenocopies the vascular and signaling defects resulting from constitutive disruption of the <i>RASA1</i> gene. In SynGAP, mutation of the equivalent conserved C2 domain surface impairs catalytic activity. Our results indicate that the C2 domain is required to achieve full catalytic activity of GAPs for Ras.
Authors
- Thomas L. Saunders (ORCID: https://orcid.org/0000-0003-2015-101X)
- Titus J. Boggon (ORCID: https://orcid.org/0000-0003-2862-1637)
- Kimberly J. Vish (ORCID: https://orcid.org/0000-0002-9394-1218)
- Nathaniel L. Lartey (ORCID: https://orcid.org/0000-0002-9810-2720)
- Zachary T. Freeman (ORCID: https://orcid.org/0000-0003-1291-382X)
- M Paul (ORCID: https://orcid.org/0000-0001-5551-1893)
- Philip D. King (ORCID: https://orcid.org/0000-0002-5598-2748)
- Elizabeth Hughes (ORCID: https://orcid.org/0000-0002-4480-0806)
- Amy L. Stiegler (ORCID: https://orcid.org/0000-0003-0453-6104)
- Di Chen (ORCID: https://orcid.org/0000-0002-5202-566X)
Institutions
- University of Michigan (US)
- Yale Cancer Center (US)
- Yale University (US)
Publication Details
- Journal
- Proceedings of the National Academy of Sciences
- Published
- 2025-02-03
- DOI
- https://doi.org/10.1073/pnas.2418433122
- Citations
- 3
- Primary Topic
- Cellular transport and secretion
- Type
- article
- Field-Weighted Citation Impact
- 3.45
Funders
- U.S. Department of Energy
- National Institutes of Health
- Office of Science
- National Heart, Lung, and Blood Institute
- National Cancer Institute
- National Institute of General Medical Sciences
- National Institute of Neurological Disorders and Stroke
- Office of Research Infrastructure Programs, National Institutes of Health
- Argonne National Laboratory