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Updated: Jun 17, 2026
14:48
Flow Cytometric Isolation of Primary Murine Type II Alveolar Epithelial Cells for Functional and Molecular Studies
Published on: December 26, 2012
Plasma membrane trafficking in alveolar type II cells
Susanne Albrecht1, Shariq M Usmani, Paul Dietl
1Institute of General Physiology, University of Ulm, Ulm, Germany.
Summary
Stimulating alveolar type II cells enhances the transport of plasma membrane components to lamellar bodies (LBs). This process utilizes a clathrin-independent endocytosis pathway, crucial for surfactant recycling.
Area of Science:
- Cell Biology
- Pulmonary Physiology
- Membrane Trafficking
Background:
- Alveolar type II (ATII) cells are vital for lung function, producing and recycling surfactant via lamellar bodies (LBs).
- Understanding the dynamic exchange of membrane components between the plasma membrane and LBs is key to pulmonary health.
Purpose of the Study:
- To investigate the trafficking mechanisms of plasma membrane proteins and lipids to LBs in ATII cells.
- To determine the role of endocytosis pathways in the transport of membrane components to LBs.
Main Methods:
- Over-expression of LAMP-3-GFP and DsRed-Farn in ATII cells to track membrane components.
- Stimulation of cells with secretagogues and treatment with various endocytosis inhibitors (phenylarsine oxide, filipin, indomethacin).
- Analysis of DsRed-Farn accumulation on LB membranes using fluorescence microscopy.
Main Results:
- DsRed-Farn, a plasma membrane marker, accumulated in discrete domains on a subset of LBs.
- Secretagogue stimulation significantly increased the surface area of these DsRed-Farn domains on LBs.
- Inhibition of clathrin-independent endocytosis, but not clathrin-dependent endocytosis, abolished this increase.
Conclusions:
- Secretagogues promote the transfer of plasma membrane components to LBs.
- This transport occurs via a clathrin-independent endocytic pathway.
- Inhibitors of intracellular vesicular transport also block this process, highlighting its dependence on vesicular mechanisms.
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