Related Experiment Video
Updated: Dec 8, 2025
10:02
Applications of pHluorin for Quantitative, Kinetic and High-throughput Analysis of Endocytosis in Budding Yeast
Published on: October 23, 2016
11.2K
Yeast Rgd3 is a phospho-regulated F-BAR-containing RhoGAP involved in the regulation of Rho3 distribution and cell
Robert M Gingras1, Kyaw Myo Lwin1, Abigail M Miller1
1Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853.
Molecular Biology of the Cell
|September 17, 2020
Summary
Rgd3, a novel RhoGAP, modulates cell polarity by regulating Rho3 localization and Myo2 activity in budding yeast. This protein is crucial for maintaining polarized growth and vesicle transport.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Polarized growth in budding yeast depends on integrating polarity pathways with exocytic vesicle delivery.
- Myosin-V (Myo2) and kinesin-related protein (Smy1) facilitate Sec4-dependent transport of secretory vesicles.
- Understanding the regulation of polarity pathways is key to cell expansion and endocytic balance.
Purpose of the Study:
- To identify novel regulators of polarized growth in budding yeast.
- To investigate the function of the F-BAR domain-containing RhoGAP, Rgd3.
- To elucidate the role of Rgd3 in Rho GTPase regulation and vesicle transport.
Main Methods:
- Genetic screening of myo2 smy1 mutants to identify suppressors.
- Localization studies of tagged Rho3 and Rgd3 using microscopy.
- In vitro liposome binding assays and protein activity assays.
- Phosphorylation site mimetic analysis and Myo2 activation assays.
Main Results:
- Rgd3, a novel RhoGAP, was identified as an overexpression suppressor of myo2 smy1 mutants.
- Rgd3 localizes to dynamic polarized vesicles and regulates the plasma membrane localization of Rho3.
- Rgd3's activity and localization are dependent on its phosphorylation state and association with PIP2.
- Rgd3 activates Myo2 in a phospho-dependent manner and rescues myo2 smy1 mutant phenotypes.
Conclusions:
- Rgd3 plays a critical role in modulating and maintaining Rho3 polarity during budding yeast growth.
- Rgd3 integrates polarity pathways by regulating Rho GTPase activity and Myo2-dependent transport.
- Rgd3 represents a novel link between Rho GTPase signaling, vesicle transport, and polarized cell growth.
Related Concept Videos
01:28Yeast Signaling
16.8K
Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes (cells with a nucleus). Cell signaling in yeast is similar to signaling in other eukaryotic cells. A ligand, such as a protein or a small molecule released from a yeast cell, attaches to a receptor on the cell surface. The binding stimulates second-messenger kinases to activate or inactivate transcription factors that further regulate gene expression. Many of the yeast intracellular signaling cascades have similar...
16.8K
01:24Small GTPases - Ras and Rho
5.0K
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:
5.0K
01:14Rab Proteins
4.8K
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 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...
4.8K
01:21Cell Polarization by Rho Proteins
3.4K
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,...
3.4K
02:15The Contractile Ring
6.9K
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...
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...
6.9K
01:33Overview of Secretory Vesicles
9.1K
Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
9.1K