Related Experiment Video
Updated: Aug 10, 2026
10:27
Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
Published on: March 9, 2012
A Ras subfamily GTPase shows cell cycle-dependent nuclear localization
B W Sutherland1, G B Spiegelman, G Weeks
1Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
EMBO Reports
|October 19, 2001
Summary
Dictyostelium RasB protein, unlike other Ras proteins, is found in the nucleus. RasB
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Ras subfamily proteins typically function in signal transduction at the plasma membrane.
- Their role in intracellular processes is less understood.
Purpose of the Study:
- To investigate the subcellular localization and function of the Dictyostelium Ras subfamily protein RasB.
- To explore the novel roles of RasB beyond plasma membrane signaling.
Main Methods:
- Immunofluorescence microscopy to determine RasB localization during the cell cycle.
- Analysis of rasB- knockout cells and cells overexpressing activated RasB.
Main Results:
- RasB predominantly localizes to the nucleus during interphase.
- RasB exhibits diffuse cellular localization during mitosis and cytokinesis.
- rasB- cells show severe growth defects.
- Overexpression of activated RasB leads to multinucleation.
Conclusions:
- RasB possesses a novel nuclear localization and function.
- RasB plays a critical role in nuclear division and cell cycle progression.
- RasB's function extends beyond the canonical plasma membrane-associated Ras signaling pathways.
Related Concept Videos
02:14GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
01:42Directionality of Nuclear Transport
Ras-related nuclear protein or Ran is a small G protein that cycles between its GTP and GDP bound states. Ran specific regulators, a Ran GTPase Activating Protein or RanGAP present in the cytosol and a Ran guanine nucleotide exchange factor or RanGEF present inside the nucleus regulate GTP/GDP exchange. A high concentration of GTP inside the cells, in addition to this asymmetric distribution of Ran-specific regulators, leads to a higher RanGTP concentration inside the nucleus. This...
02:38The Ras Gene
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...
Ras is a superfamily...
02:14GTPases and their Regulation
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Large G-proteins, also known...
01:25Rab Cascades
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.
01:24Small GTPases - Ras and Rho
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: