Related Experiment Video

Updated: Jun 20, 2026

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

Cullin mediates degradation of RhoA through evolutionarily conserved BTB adaptors to control actin cytoskeleton

Yuezhou Chen1, Zhenxiao Yang, Min Meng

  • 1College of Life Science, Peking University, Beijing 100871, China.

Molecular Cell
|September 29, 2009
PubMed

Insights

This study reveals that the Cul3/BACURD ubiquitin ligase complex controls cell shape and migration by regulating RhoA degradation. This finding uncovers a new mechanism for RhoA function in biological processes.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Developmental Biology

Background:

  • Cullin 3 (Cul3) is a scaffold protein involved in assembling ubiquitin ligase complexes.
  • The precise mechanisms and substrates of Cul3-based ubiquitin ligases are largely unknown.
  • Cul3 plays a critical role in early embryonic development.

Purpose of the Study:

  • To elucidate the function of Cul3 ubiquitin ligases in human cells and embryonic development.
  • To identify novel substrate-recruiting adaptors for Cul3.
  • To understand the role of Cul3 in regulating the small GTPase RhoA.

Main Methods:

  • Cul3 knockdown in human cells.
  • Analysis of actin stress fibers and cell morphology.
  • Identification and characterization of RhoA-binding BTB domain adaptors (BACURDs).
  • Ubiquitination assays for RhoA.
  • Functional studies in Xenopus gastrulation.

Main Results:

  • Cul3 knockdown leads to abnormal actin stress fibers and cell morphology due to impaired RhoA ubiquitination and degradation.
  • A novel family of Cul3 adaptors, BACURDs, was identified, which selectively ubiquitinate RhoA.
  • The Cul3/BACURD complex dysfunction impairs cell migration and RhoA-mediated movements in Xenopus embryos.

Conclusions:

  • The Cul3/BACURD ubiquitin ligase complex represents a novel mechanism for controlling RhoA degradation.
  • This pathway is crucial for regulating RhoA function in cell morphology, migration, and embryonic development.
  • The findings provide new insights into the diverse roles of Cul3-based ligases in biological contexts.

More Related Videos

Immunofluorescence Analysis of Endogenous and Exogenous Centromere-kinetochore Proteins05:35

Immunofluorescence Analysis of Endogenous and Exogenous Centromere-kinetochore Proteins

Published on: March 3, 2016

Aip1p Dynamics Are Altered by the R256H Mutation in Actin08:57

Aip1p Dynamics Are Altered by the R256H Mutation in Actin

Published on: July 30, 2014

Related Concept Videos

Cytoskeletal Coordination in Cell Migration01:32

Cytoskeletal Coordination in Cell Migration

A migrating cell changes its shape during the cyclic events of attachment and detachment from the substratum and repositions the cell organelles correspondingly. These complex events are orchestrated by the dynamic cytoskeletal network comprising actin filaments, intermediate filaments, and microtubules. Cytoskeletal crosstalk — the direct and indirect communication between the different components — is crucial for this coordination. Direct communication involves various linker proteins that...
Small GTPases - Ras and Rho01:24

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:
Cell Motility through Blebbing01:16

Cell Motility through Blebbing

Blebs are a type of membrane protrusion formed by the internal hydrostatic pressure of the cytoplasm. Blebs are observed in several cell types, including fibroblasts, immune cells, and single-celled organisms like the amoeba. The primary function of blebs is cell locomotion and apoptosis, but they are also found during necrosis and cell division. The life cycle of a bleb comprises an initiation phase followed by the expansion and retraction phases.
Blebbing Through the Matrix
In multicellular...
Cell Polarization by Rho Proteins01:21

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,...
The Contractile Ring02:15

The Contractile Ring

Contractile rings are composed of microfilaments and are responsible for separating the daughter cells during cytokinesis. Contractile ring assembly proceeds along with other cell cycle events; however, very few mechanistic details are known about the timing and coordination of the contractile rings with the cell cycle.
A small GTPase, RhoA, controls the function and assembly of the contractile ring. RhoA belongs to the Ras superfamily of proteins. The activation of formins by RhoA promotes...
Actin Filament Depolymerization01:19

Actin Filament Depolymerization

Actin filaments (F-actin) are composed of actin subunits. The dissociation of actin monomers can occur from either end of F-actin. The rate of dissociation is faster from the minus-end or the pointed end, where the actin subunits exist with a bound ADP, together known as ADP-actin. The depolymerization of F-actin is aided by proteins, including the actin-depolymerizing factor (ADF) and cofilin family of proteins, gelsolin, and glia maturation factor (GMF).
In F-actin, the ADF/cofilin proteins...