Ras Proteins
Ras Proteins - Related Videos
02:38
The Ras Gene
0 Views •
2021
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 superfamily...
02:38
The Ras Gene
0 Views •
2023
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 superfamily...
01:24
Small GTPases - Ras and Rho
0 Views •
2023
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: Guanine nucleotide exchange factors or GEF, GTPase-activating proteins or GAPs, and Guanine nucleotide-dissociation inhibitors or GDIs. The GEF activates the GTPase by exchanging the bound-GDP with GTP. The GTPases’...
08:12
Identification of EGFR and RAS Inhibitors using Caenorhabditis elegans
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Cited by 4 •
2020
The genetically tractable nematode Caenorhabditis elegans can be used as a simple and inexpensive model for drug discovery. Described here is a protocol to identify anticancer therapeutics that inhibit the downstream signaling of RAS and EGFR proteins.
08:46
Green Fluorescent Protein-based Expression Screening of Membrane Proteins in Escherichia coli
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Cited by 34 •
2015
A streamlined approach to screening for the expression of recombinant membrane proteins in Escherichia coli based on fusion to green fluorescent protein is presented.
FAQs
Ras signaling is controlled by reversible nucleotide exchange. In its GDP-bound state, Ras is inactive; conversion to the GTP-bound state turns signaling on, while termination returns the system toward inactivity. This switching arrangement lets receptor-derived signals be relayed for a limited period and links changes in nucleotide state to downstream effects on growth, division, differentiation, and survival.
GEFs and GAPs provide opposing control over Ras proteins. GEFs promote activation by favoring entry into the GTP-bound state, while GAPs accelerate signal termination and help shift activity away from that state. Their coordinated action determines the timing and persistence of signaling, allowing a receptor-derived message to produce a regulated response rather than an indefinitely sustained one.
Once Ras is active, it can engage the Raf-MEK-ERK cascade, a sequence that carries the signal from the molecular switch toward changes in gene expression. Those gene-expression changes can alter cellular behavior, including growth, division, differentiation, and survival. The cascade therefore links information received at the cell surface with longer-lasting biological responses inside the cell.
Mutations that lock Ras proteins in the active state remove the normal dependence on regulated GDP-to-GTP cycling. Persistent downstream signaling can then continue without appropriate control and promote uncontrolled proliferation. This behavior explains why altered Ras proteins are important in cancer research: investigators can connect a molecular defect in switching with a cellular outcome associated with tumor development.
In developmental biology, Ras signaling provides a framework for relating cell-surface receptor inputs to changes in gene expression and cell behavior. Because those outputs include growth, division, differentiation, and survival, the pathway can help explain how external signals influence developmental decisions. Its value in this context lies in connecting receptor-level communication with coordinated changes in cells.
Ras proteins are relevant to therapeutic development because mutations that maintain active signaling can drive uncontrolled proliferation. Understanding the GDP- and GTP-linked states, the regulators that control switching, and the Raf-MEK-ERK output provides a biological basis for investigating abnormal signaling. This context connects molecular pathway analysis with efforts to address cancer-associated Ras activity.