Open AccessThe pilus‐induced Ca 2+ flux triggers lysosome exocytosis and increases the amount of Lamp1 accessible to Neisseria IgA1 protease
Author(s) -
Ayala B. Patricia,
Vasquez Brandi,
Clary Susan,
Tainer John A.,
Rodland Karin,
So Magdalene
Publication year - 2001
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1046/j.1462-5822.2001.00112.x
Subject(s) - protease , lamp1 , exocytosis , lysosome , biology , microbiology and biotechnology , endocytosis , pilus , biochemistry , secretion , cell , enzyme , virulence , gene
The IgA1 protease secreted by the pathogenic Neisseriae cleaves Lamp1, a major integral membrane glycoprotein of lysosomes, and significantly reduces its steady‐state levels in an infected cell. IgA1 protease hydrolysis of Lamp1 is inefficient at the low pH of lysosomes, strongly suggesting that the enzyme is unlikely to reduce Lamp1 levels within lysosomes to any appreciable extent. We therefore explored the possibility that the protease may reach Lamp1 through an alternative route. We demonstrate that Neisseria pili induce a transient increase in the levels of cytosolic free Ca 2+ in A431 human epithelial cells, as demonstrated previously for ME180 cells. This Ca 2+ flux triggers lysosome exocytosis, quickly altering the cellular distribution of Lamp1 and increasing surface Lamp1 levels. Finally, we demonstrate that surface Lamp1 is cleaved by IgA1 protease secreted by adherent bacteria. We conclude that the pilus‐induced Ca 2+ flux increases the amount of Lamp1 that is cleavable by the IgA1 protease.