Related Experiment Video
Updated: Mar 17, 2026
08:13
Manipulation and Analysis of Cell Cycle-Dependent Processes in Budding Yeast
Published on: September 26, 2025
666
Parallel Actin-Independent Recycling Pathways Polarize Cdc42 in Budding Yeast
Benjamin Woods1, Helen Lai1, Chi-Fang Wu1
1Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
Current Biology : CB
|August 2, 2016
Summary
The Rho-family GTPase Cdc42 is crucial for cell polarity. New findings reveal that guanine nucleotide dissociation inhibitor (GDI) and GTPase-activating protein (GAP) pathways cooperate to maintain Cdc42 concentration at the cell front.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Cdc42, a Rho-family GTPase, is vital for establishing cell polarity by concentrating at cortical sites.
- This concentration requires balancing Cdc42 loss via diffusion with recycling to the cell front.
- In yeast, guanine nucleotide dissociation inhibitor (GDI) Rdi1 recycles Cdc42, but other pathways likely exist.
Purpose of the Study:
- To investigate alternative Cdc42 recycling pathways beyond Rdi1.
- To explore the role of actin in Cdc42 concentration.
- To uncover novel regulators of Cdc42 polarization.
Main Methods:
- Genetic analysis of Saccharomyces cerevisiae mutants (e.g., rdi1Δ, bem2Δ).
- Observation of Cdc42 localization and dynamics.
- Computational modeling of Cdc42 exchange between membrane and cytoplasm.
Main Results:
- F-actin does not play a role in Cdc42 concentration, even when Rdi1 is absent.
- Cdc42 exchanges between the membrane and cytoplasm, with GDP-Cdc42 exchange being faster.
- GTPase-activating protein (GAP) Bem2 has a novel role in Cdc42 polarization, acting in parallel with Rdi1.
Conclusions:
- Cell polarity is maintained by membrane-cytoplasm exchange of Cdc42, sufficient for polarization.
- GDI and GAP activities cooperate to counteract Cdc42 diffusion away from the polarity site.
- A previously unappreciated pathway allows GTP-Cdc42 to escape the polarity site, which is counteracted by GAP activity.
Related Concept Videos
01:21Cell Polarization by Rho Proteins
4.0K
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,...
4.0K
01:31Mechanism of Lamellipodia Formation
3.9K
Cells migrating in response to external stimuli form lamellipodia, which are thin membrane protrusions supported by a mesh of linked, branched, or unbranched actin filaments. These actin filaments interact with myosin motor proteins, creating the dynamic actomyosin complex within the cytoskeleton. Contractility, or the ability to generate contractile stress, is inherent to the actomyosin complex. It helps cells detect the stiffness of the surrounding ECM and exert contractile force for...
3.9K
01:39Mechanism of Filopodia Formation
3.4K
Filopodia are thin, actin-rich cellular protrusions that play an important role in many fundamental cellular functions. They vary in their occurrence, length, and positioning in different cell types, suggesting their diverse roles.
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
3.4K
02:17Separation of Sister Chromatids
4.7K
At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
At the onset of anaphase, separase, a proteolytic enzyme, is...
4.7K
01:13Actin Polymerization and Cell Motility
7.1K
Actin is a family of globular proteins that are highly abundant in eukaryotic cells. It makes up approximately 1-5% of total cell protein concentration. Actin monomers polymerize to form a complex network of polarized filaments, the actin cytoskeleton, that plays a crucial role in many cellular processes, including cell motility, division, endocytosis, and metastasis of cancer cells.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate....
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate....
7.1K
01:32Cytoskeletal Coordination in Cell Migration
5.7K
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...
5.7K