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Applications of pHluorin for Quantitative, Kinetic and High-throughput Analysis of Endocytosis in Budding Yeast
Published on: October 23, 2016
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Membrane targeting of the yeast exocyst complex
Roman Pleskot1, Lukasz Cwiklik2, Pavel Jungwirth3
1Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 165 02 Prague, Czech Republic; Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague, Czech Republic.
Biochimica Et Biophysica Acta
|April 4, 2015
Summary
The exocyst complex, crucial for exocytosis, requires phosphatidylinositol (4,5)-bisphosphate (PIP2) for proper function. Molecular simulations reveal how exocyst subunits Sec3p and Exo70p interact with PIP2, ensuring correct assembly and cellular processes.
Area of Science:
- Cell Biology
- Molecular Biophysics
- Biochemistry
Background:
- Exocytosis is vital for cellular functions, involving vesicle fusion with the plasma membrane.
- The exocyst complex, composed of eight subunits including Sec3p and Exo70p, mediates initial vesicle tethering.
- Sec3p and Exo70p are known to interact with phosphatidylinositol (4,5)-bisphosphate (PIP2) on the plasma membrane.
Purpose of the Study:
- To elucidate the structural mechanisms of yeast Sec3p and Exo70p interaction with PIP2-containing lipid bilayers.
- To understand the role of PIP2 in the assembly of the Rho1p-exocyst-membrane complex.
Main Methods:
- Coarse-grained molecular dynamics simulations were employed.
- Interactions between yeast Sec3p, Exo70p, and lipid bilayers with PIP2 were analyzed.
Main Results:
- Sec3p's N-terminal domain binds PIP2 via a positively charged pocket.
- Exo70p interacts with the membrane through multiple binding sites, inducing PIP2 clustering.
- PIP2 is essential for positioning the Rho1p GTPase for functional exocyst assembly.
Conclusions:
- The plasma membrane's PIP2 pool is critical for exocyst complex function.
- Specific interactions with acidic phospholipids like PIP2 represent an ancestral regulatory mechanism for the exocyst.
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