Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Small GTPases - Ras and Rho

Small 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:

Rab Proteins

Rab Proteins

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 Cascades

Rab 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.

Coat Assembly and GTPases

Coat Assembly and GTPases

Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...

Cell Polarization by Rho Proteins

Cell Polarization by Rho Proteins

Cell polarity is the asymmetric distribution of cellular and membrane components, making one side of the cell different from the other. This polarity is essential to many processes such as embryogenesis, axon migration, glucose transport across epithelial cells, and directional cell migration. A migrating cell responds to intracellular or extracellular signals via molecular cascades that reorganize the actin cytoskeleton to establish this polarity. In these cells, the Rho family proteins Cdc42,...

GTPases and their Regulation

GTPases 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...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Cross-Sectional Inverse Association of Regular Soy Intake with Insulin Resistance in Japanese Elderly.

Journal of nutrition in gerontology and geriatrics·2018

Same author

Structural basis for the altered drug sensitivities of non-small cell lung cancer-associated mutants of human epidermal growth factor receptor.

Oncogene·2012

Same author

Long-term effects of hepatocyte growth factor gene therapy in rat myocardial infarct model.

Gene therapy·2011

Same author

Expression of desmoglein-I cell-adhesion molecule in primary tumors and metastatic lymph-nodes of esophageal cancer.

International journal of oncology·2011

Same author

Asef2 and Neurabin2 cooperatively regulate actin cytoskeletal organization and are involved in HGF-induced cell migration.

Oncogene·2009

Same author

Expression of pentraxin 3 (PTX3) in human atherosclerotic lesions.

The Journal of pathology·2008

Search research articles

Related Experiment Video

Updated: Jul 14, 2026

Comparing the Affinity of GTPase-binding Proteins using Competition Assays

Comparing the Affinity of GTPase-binding Proteins using Competition Assays

Published on: October 8, 2015

Identification and characterization of Asef2, a guanine-nucleotide exchange factor specific for Rac1 and Cdc42.

Y Kawasaki¹, M Sagara, Y Shibata

¹Laboratory of Molecular and Genetic Information, Institute for Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan.

|June 30, 2007

Summary

A newly discovered protein, Asef2, interacts with the adenomatous polyposis coli (APC) protein to regulate cell migration. This interaction is crucial for colorectal tumor cell movement, especially when APC is mutated.

More Related Videos

Affinity Precipitation of Active Rho-GEFs Using a GST-tagged Mutant Rho Protein (GST-RhoA(G17A)) from Epithelial Cell Lysates

Affinity Precipitation of Active Rho-GEFs Using a GST-tagged Mutant Rho Protein (GST-RhoA(G17A)) from Epithelial Cell Lysates

Published on: March 31, 2012

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells

Published on: March 9, 2012

Related Experiment Videos

Last Updated: Jul 14, 2026

Comparing the Affinity of GTPase-binding Proteins using Competition Assays

Comparing the Affinity of GTPase-binding Proteins using Competition Assays

Published on: October 8, 2015

Affinity Precipitation of Active Rho-GEFs Using a GST-tagged Mutant Rho Protein (GST-RhoA(G17A)) from Epithelial Cell Lysates

Affinity Precipitation of Active Rho-GEFs Using a GST-tagged Mutant Rho Protein (GST-RhoA(G17A)) from Epithelial Cell Lysates

Published on: March 31, 2012

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells

Published on: March 9, 2012

Area of Science:

Cell Biology
Molecular Biology
Cancer Research

Background:

The adenomatous polyposis coli (APC) tumor suppressor is frequently mutated in colorectal cancers.
APC interacts with the Rac1-specific guanine-nucleotide exchange factor (GEF) Asef, influencing cell adhesion and migration.
Asef possesses an APC-binding region (ABR), Dbl homology (DH), Pleckstrin (PH), and Src homology 3 (SH3) domains.

Purpose of the Study:

To identify and characterize a novel Asef homolog, termed Asef2.
To investigate the interaction domains of Asef2 with APC.
To determine the role of Asef2 in cell migration, particularly in the context of colorectal tumors with APC mutations.

Main Methods:

Protein interaction studies to identify Asef2 and its binding domains.
Expression of full-length and mutant Asef2 in cell lines (HeLa, MDCK).
Analysis of active Rac1 and Cdc42 levels.
RNA interference to assess Asef2's role in cell migration.

Main Results:

Asef2 shares structural and functional similarities with Asef.
The N-terminal ABR and SH3 domains of Asef2 mediate its interaction with APC.
Asef2, particularly when co-expressed with truncated APC, promotes active Rac1/Cdc42, lamellipodia, and filopodia formation.
Asef2 is essential for the migration of colorectal tumor cells with truncated APC.

Conclusions:

Asef2 is a functional homolog of Asef, playing a significant role in cell migration.
Asef2, activated by truncated APC, contributes to the aberrant migration characteristic of colorectal tumor cells.
Targeting the Asef2-APC interaction may offer therapeutic strategies for colorectal cancer.