Cell Biology

Resection and Repair

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Science  21 Mar 2008:
Vol. 319, Issue 5870, pp. 1591
DOI: 10.1126/science.319.5870.1591a

When the outer membrane of a eukaryotic cell is damaged (for instance, by ripping), a calcium-dependent repair process involving the fusion of lysosomal membrane with the plasma membrane is set in motion. Bacterial toxins can also perforate the plasma membrane, but do so by forming protein-delimited holes. How does a cell repair this kind of puncture? Idone et al. show that, in addition to patching the portion of damaged membrane using exocytosis, the cell arranges for the removal of the perforated areas from the cell surface via a process of calcium-stimulated endocytosis. Treating cells with the bacterial toxin streptolysin, which forms stable membrane-embedded pores, induced a calcium- and sterol-dependent form of endocytosis that cleared the pores from the plasma membrane, leading to the rapid (in less than a minute) resealing of the cell; independently stimulating endocytosis also promoted membrane repair. Thus, cells use two mechanistically linked pathways, which are both stimulated by high levels of extracellular calcium, to activate membrane repair after physical injury. — SMH

J. Cell Biol. 180, 905 (2008).

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