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A Charge Swap mutation E461K in the yeast dynamin Vps1 reduces endocytic invagination
Sarah E Palmer1, Iwona I Smaczynska-de Rooij1, Christopher J Marklew1
1Department of Biomedical Science; University of Sheffield ; Sheffield, UK.
Abstract:
Vps1 is the yeast dynamin-like protein that functions during several membrane trafficking events including traffic from Golgi to vacuole, endosomal recycling and endocytosis. Vps1 can also function in peroxisomal fission indicating that its ability to drive membrane fission is relatively promiscuous. It has been of interest therefore that several mutations have been identified in Vps1 that only disrupt its endocytic function. Most recently, disruption of the interaction with actin through mutation of residues in one of the central stalk α helices (RR457,458 EE) has been shown to disrupt endocytosis and cause an accumulation of highly elongated invaginations in cells. This data supports the idea that an interaction between Vps1 and actin is important to drive the scission stage in endocytosis. Another Vps1 mutant generated in the study was vps1 E461K. Here we show data demonstrating that the E461K mutation also disrupts endocytosis but at an early stage, resulting in inhibition of the invagination step itself.
Insights
Vesicle trafficking protein Vps1 is crucial for yeast endocytosis. Mutations reveal its interaction with actin is vital for membrane scission, while another mutation inhibits early invagination.
Area of Science:
- Cell biology
- Molecular and cell biology
- Membrane trafficking
Background:
- Vesicle-mediated transport is essential for cellular function.
- Dynamin-like proteins, such as yeast Vps1, play critical roles in membrane fission.
- Specific Vps1 functions in endocytosis and peroxisomal fission have been observed.
Purpose of the Study:
- To investigate the role of Vps1 in endocytosis.
- To elucidate the functional consequences of specific Vps1 mutations.
- To understand the interaction between Vps1 and actin in membrane trafficking.
Main Methods:
- Site-directed mutagenesis of Vps1.
- Analysis of Vps1 function in yeast endocytosis.
- Microscopy to observe cellular morphology.
Main Results:
- A mutation (RR457,458 EE) disrupting Vps1-actin interaction impairs endocytosis, causing elongated invaginations.
- The vps1 E461K mutation inhibits an early stage of endocytosis, specifically the invagination step.
- Vps1's role in membrane scission during endocytosis is supported by these findings.
Conclusions:
- Vps1's interaction with actin is critical for the scission phase of endocytosis.
- The E461K mutation affects an earlier step in endocytosis, impacting membrane invagination.
- Vps1 exhibits distinct functional roles dependent on specific protein interactions and mutations.
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