Related Experiment Video
Updated: Dec 26, 2025
08:49
Fluorescence-Based Measurements of Phosphatidylserine/Phosphatidylinositol 4-Phosphate Exchange Between Membranes
Published on: March 14, 2021
4.5K
A heat-sensitive Osh protein controls PI4P polarity
Deike J Omnus1,2, Angela Cadou1, Ffion B Thomas1
1MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
BMC Biology
|March 15, 2020
Summary
Phosphatidylinositol 4-phosphate (PI4P) distribution is regulated by Osh proteins, controlling polarized secretion. Heat stress alters PI4P distribution via Osh3, impacting cell growth and migration.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Phosphoinositide lipids act as spatial landmarks in cell polarity.
- Mechanisms orienting phosphoinositide gradients to extracellular cues remain unclear.
- This study investigates phosphatidylinositol 4-phosphate (PI4P) regulation in polarized secretion.
Purpose of the Study:
- To elucidate the regulation of PI4P distribution by Osh proteins.
- To understand how environmental conditions like heat stress affect PI4P localization.
- To determine the role of PI4P in polarized secretion and cell growth.
Main Methods:
- Observation of PI4P localization in budding yeast under normal and heat stress conditions.
- Analysis of Osh protein function, specifically Osh3, and its domains.
- Assessment of exocyst component Exo70 distribution.
Main Results:
- PI4P is enriched at the plasma membrane of growing daughter cells.
- Heat stress causes a uniform PI4P distribution by increasing PI4P in mother cells.
- Osh proteins, particularly Osh3, mediate PI4P distribution; Osh3 undergoes heat-induced aggregation.
- Loss of Osh3 function impairs polarized PI4P and Exo70 distribution.
Conclusions:
- Osh proteins are key regulators of PI4P metabolism.
- PI4P metabolism controlled by Osh proteins is crucial for polarized growth and secretion.
- Osh3's heat sensitivity influences PI4P localization and secretory trafficking.
More Related Videos
Related Concept Videos
01:42Phosphoinositides and PIPs
10.0K
Phosphoinositides are a group of phospholipids containing a glycerol backbone with two fatty acid chains and a phosphate attached to a myoinositol sugar ring. The inositol head group extends into the cytoplasm, where it is modified by adding phosphate groups to form phosphatidylinositol phosphates or PIPs.
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
10.0K
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
01:11IP3/DAG Signaling Pathway
14.0K
Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and...
14.0K
01:20The JAK-STAT Signaling Pathway
11.6K
Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as SH2...
11.6K
01:39Mechanism of Filopodia Formation
2.9K
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...
2.9K
01:22PI3K/mTOR/AKT Signaling Pathway
5.1K
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast, mTORC2 consists of a...
5.1K