Related Experiment Video
Updated: Jan 11, 2026
07:49
Characterize Disease-related Mutants of RAF Family Kinases by Using a Set of Practical and Feasible Methods
Published on: July 17, 2019
6.5K
Clinically observed RASA1 missense mutants exhibit diverse RasGAP protein behaviors
Maxum E Paul1, Rediet B Delelegne2, Jocelyn E Chau1
1Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA 06520.
Biorxiv : the Preprint Server for Biology
|November 19, 2025
Summary
Mutations in the RASA1 gene cause cerebrovascular disorders and cancer. This study categorizes these RASA1 mutations by how they disrupt RasGAP protein function, revealing distinct dysregulation mechanisms.
Area of Science:
- Genetics and Molecular Biology
- Biochemistry
- Structural Biology
Background:
- The RASA1 gene encodes the RasGAP (p120RasGAP) protein, crucial for regulating cellular signaling.
- Mutations in RASA1 are linked to cerebrovascular disorders and various cancers.
- The precise mechanisms by which RASA1 mutations dysregulate RasGAP signaling are not fully understood.
Purpose of the Study:
- To catalogue known disease-associated mutations in RASA1.
- To experimentally assess the impact of these mutations on RasGAP protein function, stability, and interactions.
- To classify RASA1 mutations based on their distinct mechanisms of dysregulating RasGAP signaling.
Main Methods:
- Cataloguing reported RASA1 mutations and mapping them onto structural models of RasGAP.
- In vitro assessment of mutant RasGAP protein expression, thermal stability, and interaction with p190RasGAP.
- Enzyme kinetics (Michaelis-Menten) analysis of mutant RasGAP activity towards Ras.
- Structure-function analysis of specific mutation sites.
Main Results:
- Disease-associated RASA1 mutations were mapped to specific regions of the RasGAP protein.
- Mutations impact protein expression, stability, and interactions with binding partners.
- Mutant RasGAP proteins exhibit distinct kinetic profiles, classifying mutations into different dysregulation categories.
- Protein stability is essential but not sufficient for full RasGAP catalytic activity.
- The C2 domain plays a unique role in regulating GAP activity through residue-specific interactions, independent of overall protein destabilization.
Conclusions:
- Disease-associated RASA1 mutations can be classified into distinct mechanistic groups based on their impact on RasGAP function.
- Protein stability is a prerequisite for RasGAP activity, and its disruption is a common mechanism of dysregulation.
- Specific domains, like the C2 domain, employ unique mechanisms to regulate RasGAP activity, highlighting the complexity of signaling pathway control.
Related Concept Videos
02:38The Ras Gene
7.0K
The Ras-gene-encoded proteins are regulators of signaling pathways controlling cell proliferation, differentiation, or cell survival. The Ras-gene family in humans constitutes three primary members—the HRas, NRas, and KRas. These genes code for four functionally distinct yet closely related proteins—the HRas, NRas, KRas4A, and KRas4B. The involvement of mutant Ras genes in human cancer was first discovered in 1982 and is among the most common causes of human tumorigenesis.
Ras is a...
Ras is a...
7.0K
01:24Small GTPases - Ras and Rho
5.2K
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity:
5.2K
01:25Rab Cascades
3.4K
Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.
3.4K
01:14Rab Proteins
4.9K
Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
4.9K
01:07MAPK Signaling Cascades
7.8K
Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
7.8K
02:23Abnormal Proliferation
5.1K
Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the...
5.1K