Plasma Membrane Area Increases with Spread Area by Exocytosis of a GPI-anchored Protein Compartment

Nils C. Gauthier, Olivier M. Rossier, Anurag Mathur, James C. Hone, Michael P. Sheetz
MBoC. 2009-07-15; 20(14): 3261-3272
DOI: 10.1091/mbc.E09-01-0071

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1. Mol Biol Cell. 2009 Jul;20(14):3261-72. doi: 10.1091/mbc.E09-01-0071. Epub 2009
May 20.

Plasma membrane area increases with spread area by exocytosis of a GPI-anchored
protein compartment.

Gauthier NC(1), Rossier OM, Mathur A, Hone JC, Sheetz MP.

Author information:
(1)Department of Biological Sciences, Columbia University, New York, NY 10027,

The role of plasma membrane (PM) area as a critical factor during cell motility
is poorly understood, mainly due to an inability to precisely follow PM area
dynamics. To address this fundamental question, we developed static and dynamic
assays to follow exocytosis, endocytosis, and PM area changes during fibroblast
spreading. Because the PM area cannot increase by stretch, spreading proceeds by
the flattening of membrane folds and/or by the addition of new membrane. Using
laser tweezers, we found that PM tension progressively decreases during
spreading, suggesting the addition of new membrane. Next, we found that
exocytosis increases the PM area by 40-60% during spreading. Reducing PM area
reduced spread area, and, in a reciprocal manner, reducing spreadable area
reduced PM area, indicating the interconnection between these two parameters. We
observed that Golgi, lysosomes, and glycosylphosphatidylinositol-anchored protein
vesicles are exocytosed during spreading, but endoplasmic reticulum and
transferrin receptor-containing vesicles are not. Microtubule depolymerization
blocks lysosome and Golgi exocytosis but not the exocytosis of
glycosylphosphatidylinositol-anchored protein vesicles or PM area increase.
Therefore, we suggest that fibroblasts are able to regulate about half of their
original PM area by the addition of membrane via a
glycosylphosphatidylinositol-anchored protein compartment.

DOI: 10.1091/mbc.e09-01-0071
PMCID: PMC2710839
PMID: 19458190 [Indexed for MEDLINE]

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