Dr. Norma Andrews overviews the mechanisms of cellular plasma membrane repair. As she describes, a lesion is followed by a Ca2+-dependent movement of vesicles to the plasma membrane. By studying how the Trypanosoma cruzi parasite enters the cell, Andrews’ laboratory discovered that an increase of intracellular calcium was triggering lysosomal fusion to the plasma membrane. This unexpected observation allowed them to conclude that upon an injury to the plasma membrane, a Ca2+ influx induces lysosomal exocytosis mediated repair. This research demonstrates that lysosomes are not only responsible for the degradation of material that comes inside the cell through endocytosis, but also have an important role in plasma membrane repair.
In her second talk, Andrews further explains how Ca2+-dependent exocytosis of lysosomes aids membrane repair. Her laboratory showed that after lysosomal exocytosis, an injury to the plasma membrane would also trigger a Ca2+-dependent endocytosis that is required for the repair mechanism. Andrews laboratory showed that lysosomes release the enzyme acid sphingomyelinase (ASM) which induce the endocytosis required for plasma membrane repair.
Norma Andrews is currently a Professor and Chair of the Department of Cell Biology and Molecular Genetics at the University of Maryland. She received a B.S. degree in biology (1977) and a Ph.D. degree in biochemistry (1983) from the University of São Paulo, Brazil. In 1990, after completing postdoctoral studies in the laboratory of Victor… Continue Reading