Cell Biology

A Quick Fix

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Science  17 Aug 2001:
Vol. 293, Issue 5533, pp. 1223
DOI: 10.1126/science.293.5533.1223a

For an animal cell, rupture of the plasma membrane would be thought to imply certain death. However, in some instances repair is possible. Indeed it appears that mechanisms for rapid repair exist in most cell types.

Reddy et al. examined the process of plasma membrane repair in tissue culture cells wounded by scraping. Surprisingly, the repair process involved fusion of the cell's degradative organelles, the lysosomes, with the cell surface. Upon wounding, lysosomes fused with the plasma membrane, rapidly sealing the cell in a Ca2+-triggered process. The mechanism of fusion involved the lysosomal form of synaptotagmin, SytVII, and could be inhibited by expressing the cytoplasmic C2A domain of Syt VII involved in Ca2+ sensing. In primary skin fibroblasts wounded by the contraction of their supporting collagen matrix, lysosomal exocytosis was also responsible for cell resealing. Thus, in addition to degrading ingested proteins, lysosomes also play a key role in plasma membrane repair by acting as Ca2+-regulated secretory vesicles. — SMH

Cell106, 157 (2001).

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