GO:0032173 septin collar: Components, Assembly and Research Methods, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0032173 septin collar is a tubular, hourglass-shaped structure composed of highly ordered arrays of septin filaments that forms in budding yeast from an initial septin ring and expands into the daughter cell [1, 3].
• Septin collar assembly requires GTP binding and direct phosphorylation by the PAK kinase Cla4.
• Exocytic plasma membrane flows remodel endoplasmic reticulum-plasma membrane tethering to enable septin collar assembly.
• Septin assemblies promote lipid organization of membranes, linking collar formation to membrane compartmentalization.
• The septin collar is essential for cytokinesis and cell division in budding yeast, serving as a scaffold for recruiting division machinery [7, 8].
• Research on septin collars uses live-cell imaging, genetics, and proteomics, and is relevant to understanding human septin-related diseases [2, 3].
Description
The septin collar (GO:0032173) is a specialized cytoskeletal structure found in budding yeast, Saccharomyces cerevisiae. It is defined as a tubular, hourglass-shaped assembly of highly ordered septin filaments that forms at the mother-bud neck during the cell cycle [1, 3]. This structure is critical for cytokinesis and serves as a scaffold for recruiting proteins involved in cell division and polarity. Understanding the septin collar provides insights into fundamental mechanisms of cytoskeletal organization and membrane dynamics [4, 6]. Researchers study the septin collar to elucidate how cells coordinate division and to model related processes in higher eukaryotes, including humans, where septin dysfunction is linked to diseases such as cancer and neurodegeneration [2, 8].
septin collar At A Glance
| GO ID | GO:0032173 |
|---|---|
| GO term | septin collar |
| Ontology | cellular_component |
| Synonym | septin hourglass |
| Major function | Scaffold for cytokinesis and cell division; organizes septin filaments at the mother-bud neck [1, 7] |
| Composition | Highly ordered arrays of septin filaments (e.g., Cdc3, Cdc10, Cdc11, Cdc12) [3, 5] |
| Assembly requirements | GTP binding and phosphorylation by Cla4 kinase |
| Membrane interaction | Promotes lipid organization and is influenced by exocytic membrane flows [4, 6] |
What Is GO:0032173?
The septin collar is a cellular component defined by the Gene Ontology as a tubular, hourglass-shaped structure composed of highly ordered arrays of septin filaments. In budding yeast, it forms from an initial septin ring by expanding into the daughter cell [1, 3]. This structure is synonymous with the septin hourglass and is essential for organizing the site of cell division [5, 7].
Why Is septin collar Important in Cell Biology?
The septin collar is crucial for cytokinesis and cell division in budding yeast, acting as a scaffold that recruits and organizes the machinery for cell separation [7, 8]. Its study illuminates fundamental principles of cytoskeletal assembly, membrane remodeling, and cell cycle regulation [1, 4, 6]. Moreover, septins are conserved across eukaryotes, and understanding the yeast septin collar provides a model for investigating septin functions in human health and disease, including cancer and neurological disorders [2, 3].
• Essential for cytokinesis and cell division in budding yeast.
• Serves as a scaffold for recruiting division proteins and signaling molecules.
• Requires GTP binding and phosphorylation by Cla4 for proper assembly.
• Interacts with membrane lipids and exocytic pathways to coordinate membrane remodeling [4, 6].
• Provides a model for studying conserved septin functions in higher eukaryotes.
• Dysregulation of septins is implicated in human diseases such as cancer and neurodegeneration [2, 8].
• Key to understanding cell polarity and morphogenesis.
• Offers targets for antifungal drug development.
• Advances knowledge of cytoskeletal dynamics and self-assembly.
• Enables research on membrane compartmentalization and lipid organization.
What Happens During septin collar?
Initiation at the mother-bud neck
In simple terms: The septin collar starts forming at the neck between the mother cell and the bud.
In budding yeast, the septin collar begins as a ring at the mother-bud neck early in the cell cycle. This initial ring is composed of septin filaments and serves as a template for collar expansion [1, 3].
Expansion into the daughter cell
In simple terms: The ring expands into a tubular hourglass shape that extends into the bud.
The septin ring expands into the daughter cell to form the hourglass-shaped collar. This expansion is driven by the addition of septin subunits and requires GTP binding and phosphorylation by the PAK kinase Cla4.
Membrane remodeling and exocytosis
In simple terms: Membrane flow and exocytosis help shape the collar.
Exocytic plasma membrane flows remodel endoplasmic reticulum-plasma membrane tethering, which is necessary for septin collar assembly. This process ensures proper membrane organization at the division site.
Lipid organization
In simple terms: Septins help organize lipids in the membrane.
Septin assemblies promote the lipid organization of membranes, contributing to the compartmentalization required for collar function and cytokinesis.
Disassembly and cytokinesis
In simple terms: The collar splits and disassembles as the cells divide.
Upon completion of cytokinesis, the septin collar undergoes disassembly, allowing cell separation. This step is tightly regulated and involves remodeling of septin filaments [7, 8].
Key Genes Involved in GO:0032173 septin collar
Key genes and proteins involved in septin collar formation and function in budding yeast include core septins and regulatory kinases.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CDC3 | Core septin subunit | Essential for filament formation and collar assembly |
| CDC10 | Core septin subunit | Required for septin ring and collar integrity |
| CDC11 | Core septin subunit | Involved in septin filament organization |
| CDC12 | Core septin subunit | Essential for septin collar formation |
| CLA4 | PAK kinase | Phosphorylates septins for collar assembly |
| GIN4 | Kinase | Regulates septin ring dynamics |
| ELM1 | Kinase | Involved in septin phosphorylation |
| KCC4 | Kinase | Regulates septin assembly |
| BUD3 | Scaffold protein | Recruits septins to the bud neck |
| BUD4 | Scaffold protein | Coordinates septin ring formation |
| MYO1 | Myosin | Interacts with septins for cytokinesis |
| IQG1 | IQGAP | Links septins to actomyosin ring |
| CHS2 | Chitin synthase | Involved in septum formation |
| RHO1 | GTPase | Regulates septin organization |
| CDC42 | GTPase | Controls polarity and septin recruitment |
| SEP7 | Septin | Accessory septin in some species |
| SEP9 | Septin | Accessory septin in some species |
How Is septin collar Regulated?
Septin collar assembly is regulated by GTP binding and phosphorylation. The PAK kinase Cla4 directly phosphorylates septins, which is required for collar formation. Additionally, kinases such as Gin4, Elm1, and Kcc4 regulate septin dynamics and ring stability. Exocytic membrane flows and lipid organization also influence collar assembly [4, 6].
septin collar and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SEPT9 | Cancer (colorectal, breast) | Knockout in human cell lines; xenograft models |
| SEPT2 | Neurodegeneration (Alzheimer's) | Knock-in of mutations in neuronal cells |
| SEPT4 | Parkinson's disease | Overexpression in yeast and mammalian cells |
| CDC3 | Fungal infections | Yeast knockout for antifungal screening |
| CDC12 | Fungal infections | Yeast knockout for antifungal screening |
Septins in cancer
Septins are frequently dysregulated in human cancers, where they contribute to tumorigenesis by affecting cell division, migration, and apoptosis. The yeast septin collar serves as a model to understand conserved septin functions that may be targeted in cancer therapy [2, 8].
Septins in neurodegeneration
Septin mutations have been linked to neurodegenerative diseases such as Alzheimer's and Parkinson's, where septin filaments are found in pathological inclusions. Studying septin collar assembly in yeast can provide insights into the mechanisms of septin dysfunction in neurons [2, 8].
Septins in infectious diseases
Septins play roles in host-pathogen interactions, and fungal septins are potential antifungal targets. Understanding the septin collar in budding yeast may aid in developing drugs against pathogenic fungi.
From septin collar-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the role of GTP binding in septin collar assembly? | Point mutation of GTP-binding residues in septins |
| How does phosphorylation regulate collar formation? | Knockout of CLA4 kinase or phospho-mimetic mutants |
| What is the dynamics of septin collar assembly? | Tagged knock-in of fluorescent septins for live imaging |
| How do septins interact with membrane lipids? | Overexpression of septins in lipid mutant backgrounds |
| What proteins are recruited to the septin collar? | Knockout of candidate genes followed by proteomics |
| How does exocytosis affect collar assembly? | Conditional knockout of exocytic genes |
How to Study the septin collar Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Live-cell fluorescence microscopy | Septin collar dynamics and morphology | Visualizing ring-to-collar transition |
| FRAP | Septin turnover rates | Assessing filament exchange |
| Co-immunoprecipitation | Protein-protein interactions | Identifying septin complex components |
| Mass spectrometry | Post-translational modifications | Mapping phosphorylation sites |
| Lipidomics | Membrane lipid composition | Linking septins to lipid organization |
| Genetic interaction screens | Synthetic growth defects | Finding new regulators |
| Electron microscopy | Ultrastructure of septin filaments | Determining filament arrangement |
| In vitro reconstitution | Filament assembly properties | Studying GTP-dependent polymerization |
Live-cell imaging
Fluorescently tagged septins (e.g., Cdc3-GFP) allow real-time visualization of septin ring and collar dynamics in budding yeast. This method reveals the timing of ring-to-collar transition and disassembly.
Genetic screens
Knockout or conditional mutant libraries can be screened for defects in septin collar assembly, identifying new regulators. This approach has uncovered kinases and scaffold proteins [5, 7].
Proteomics
Affinity purification of septin complexes followed by mass spectrometry identifies interacting proteins and post-translational modifications, providing insights into collar composition and regulation.
Lipid analysis
Lipidomics and membrane fractionation can assess how septin assemblies influence lipid organization and membrane compartmentalization.
How CRISPR Can Be Used to Study GO:0032173 septin collar
Knockout
CRISPR knockout of core septin genes (e.g., CDC3, CDC10, CDC11, CDC12) in budding yeast or human cells can abolish septin collar formation, leading to cytokinesis defects. These models help dissect the role of individual septins in collar assembly and function [3, 7].
Point Mutation
Introducing point mutations in septin genes (e.g., in GTP-binding domains) via CRISPR allows precise testing of their roles in collar assembly. For example, mutations that impair GTP binding prevent collar formation.
Knock-in
Knock-in of fluorescent tags (e.g., GFP) or epitope tags into endogenous septin loci enables live imaging and biochemical studies of the septin collar in its native context.
Overexpression
CRISPR activation or plasmid-based overexpression of septins or regulators can induce ectopic collar formation or disrupt normal dynamics, providing insights into stoichiometry and regulation [4, 8].
How EDITGENE Supports septin collar Research
Researchers studying septin collar-related genes often need to determine whether a candidate gene is causally involved in collar assembly, dynamics, or function. EDITGENE provides comprehensive CRISPR services to create precise genetic models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for septin collar research.
Frequently Asked Questions About septin collar
What is a septin collar?
The septin collar is a tubular, hourglass-shaped structure composed of highly ordered septin filaments that forms at the mother-bud neck in budding yeast and is essential for cytokinesis [1, 3].
What genes are involved in septin collar formation?
Core septin genes include CDC3, CDC10, CDC11, and CDC12, along with regulatory kinases such as CLA4 [3, 5].
What is the function of the septin collar?
It serves as a scaffold for cytokinesis, organizing the division site and recruiting proteins required for cell separation [7, 8].
How is the septin collar assembled?
It assembles from a septin ring that expands into the daughter cell, requiring GTP binding and phosphorylation by Cla4.
What is the role of GTP in septin collar formation?
GTP binding by septins is essential for their polymerization and proper collar assembly.
How is the septin collar regulated?
It is regulated by phosphorylation (e.g., by Cla4), GTP binding, and membrane dynamics [5, 6].
What diseases are associated with septin dysfunction?
Septin mutations are linked to cancer and neurodegenerative diseases such as Alzheimer's and Parkinson's [2, 8].
What model organisms are used to study the septin collar?
Budding yeast Saccharomyces cerevisiae is the primary model, but human cell lines are also used [1, 3].
What methods are used to study septin collars?
Live-cell imaging, genetics, proteomics, and lipid analysis are common approaches [1, 4, 8].
How can CRISPR be used to study septin collars?
CRISPR enables knockout, point mutation, knock-in, and overexpression of septin genes to dissect their functions [3, 5].
Conclusion
The septin collar (GO:0032173) is a dynamic cytoskeletal structure essential for cytokinesis in budding yeast. Its assembly and function are regulated by GTP binding, phosphorylation, and membrane remodeling. Studying the septin collar provides fundamental insights into cell division and offers a model for understanding septin-related diseases in humans. EDITGENE's CRISPR services can accelerate research on septin collar components and their roles in health and disease.
References
- 1. Chen H et al.. 2011. Dynamics of septin ring and collar formation in Saccharomyces cerevisiae.. Biol Chem 392(8-9):689-97 PMID: 21736496
- 2. Kinoshita M. 2006. Diversity of septin scaffolds.. Curr Opin Cell Biol 18(1):54-60 PMID: 16356703
- 3. Farkašovský M. 2020. Septin architecture and function in budding yeast.. Biol Chem 401(8):903-919 PMID: 31913844
- 4. El Alaoui F et al.. 2025. Septin assemblies promote the lipid organization of membranes.. Structure 33(3):451-464.e5 PMID: 39892381
- 5. Versele M et al.. 2004. Septin collar formation in budding yeast requires GTP binding and direct phosphorylation by the PAK, Cla4.. J Cell Biol 164(5):701-15 PMID: 14993234
- 6. Sugiyama S et al.. 2024. Exocytic plasma membrane flows remodel endoplasmic reticulum-plasma membrane tethering for septin collar assembly.. Sci Adv 10(11):eadj1512 PMID: 38478607
- 7. Varela Salgado M et al.. 2024. Septin Organization and Dynamics for Budding Yeast Cytokinesis.. J Fungi (Basel) 10(9) PMID: 39330402
- 8. Marquardt J et al.. 2019. Architecture, remodeling, and functions of the septin cytoskeleton.. Cytoskeleton (Hoboken) 76(1):7-14 PMID: 29979831
