Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Small GTPases - Ras and Rho01:24

Small GTPases - Ras and Rho

5.7K
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:
5.7K
GTPases and their Regulation02:14

GTPases and their Regulation

10.3K
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,...
10.3K
GTPases and their Regulation02:14

GTPases and their Regulation

3.3K
3.3K
Mechanisms of Membrane-bending01:15

Mechanisms of Membrane-bending

3.7K
The living membranes are flexible due to their fluid mosaic nature; however, their bending into different shapes is an active process regulated by specific lipids and proteins. The membrane bending can be transient as seen in vesicles or stable for a long time as in microvilli. Cells regulate the size, location, and duration of the membrane curvature.
Membrane bending can happen due to intrinsic changes in lipid composition or extrinsic association with different proteins. The proteins involved...
3.7K
Coat Assembly and GTPases01:33

Coat Assembly and GTPases

4.7K
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...
4.7K
Rab Proteins01:14

Rab Proteins

5.4K
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...
5.4K

You might also read

Related Articles

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

Sort by
Same author

Author Correction: In situ cryo-ET defines the ultrastructure of ER exit sites in human cells.

Nature cell biology·2026
Same author

DNA-mimic for Specific Surface Functionalization of Zr-MOFs for Bacterial Targeting.

Angewandte Chemie (International ed. in English)·2026
Same author

In situ cryo-ET defines the ultrastructure of ER exit sites in human cells.

Nature cell biology·2026
Same author

Directed evolution of APOX for proximity labeling using phenols with high redox potentials.

Cell chemical biology·2026
Same author

Mad1 facilitates α5 integrin trafficking from the Golgi to promote abscission during cytokinesis.

Nature communications·2026
Same author

A Facile and Reproducible Method for the Purification of Peptide- and Protein-Functionalized DNA Nanostructures.

JACS Au·2025

Related Experiment Video

Updated: Mar 30, 2026

Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay
13:51

Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay

Published on: November 11, 2018

10.4K

Sar1 GTPase Activity Is Regulated by Membrane Curvature.

Michael G Hanna1, Ioanna Mela2, Lei Wang1

  • 1From the Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin 53706.

The Journal of Biological Chemistry
|November 8, 2015
PubMed
Summary

Sar1 GTPase senses membrane curvature, driving vesicle formation in the endoplasmic reticulum. Its activity, regulated by Sec23-Sec24, is essential for membrane remodeling and protein transport.

Keywords:
COPIIGTPaseendoplasmic reticulum (ER)membrane bilayermembrane transport

More Related Videos

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

11.3K
Comparing the Affinity of GTPase-binding Proteins using Competition Assays
10:37

Comparing the Affinity of GTPase-binding Proteins using Competition Assays

Published on: October 8, 2015

9.7K

Related Experiment Videos

Last Updated: Mar 30, 2026

Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay
13:51

Detection of Small GTPase Prenylation and GTP Binding Using Membrane Fractionation and GTPase-linked Immunosorbent Assay

Published on: November 11, 2018

10.4K
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

11.3K
Comparing the Affinity of GTPase-binding Proteins using Competition Assays
10:37

Comparing the Affinity of GTPase-binding Proteins using Competition Assays

Published on: October 8, 2015

9.7K

Area of Science:

  • Cell biology
  • Molecular and cell biology
  • Biochemistry

Background:

  • Biosynthetic secretory proteins traffic via the endomembrane system.
  • Sar1 GTPase is crucial for COPII coat assembly and vesicle formation at the endoplasmic reticulum.

Purpose of the Study:

  • To elucidate the role of Sar1 GTPase in coordinating membrane bending and vesicle formation.
  • To investigate Sar1's curvature-sensing mechanism and its GTPase activity in membrane remodeling.

Main Methods:

  • Atomic force microscopy to analyze Sar1's interaction with lipid bilayers.
  • Biochemical assays to study Sar1's GTPase activity and its regulation by Sec23-Sec24 and GTP analogs.

Main Results:

  • Sar1 acts as a curvature sensor, binding avidly to highly curved membranes.
  • Sar1's intrinsic GTPase activity is required for lipid bilayer remodeling.
  • Sec23-Sec24 accelerates Sar1-mediated membrane remodeling, while GTP analogs inhibit it.
  • Sar1 GTPase activity is stimulated by membrane curvature, potentially localizing scission to bud necks.

Conclusions:

  • Sar1's N-terminal helix initiates membrane deformation.
  • Increasing membrane curvature enhances Sar1 binding and stimulates GTP hydrolysis.
  • This process facilitates membrane fission during COPII vesicle formation.