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Endosomal proteolysis of internalized proteins
Author(s) -
Authier François,
Posner Barry I.,
Bergeron John J.M.
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00368-7
Subject(s) - endosome , proteases , endocytic cycle , proteolysis , microbiology and biotechnology , endocytosis , biochemistry , protease , chemistry , biology , intracellular , receptor , enzyme
Endosomal proteases have been implicated in the DAgradation of internalized regulatory peptides involved in the control of metabolic pathways and in the processing of intracellular antigens for cytolytic immune responses. Processing in the endocytic vesicles is regulated by changes in endosomal acidity due to the presence of an ATP‐DApenDAnt proton pump which modulates protease activity, protein unfolding and receptor‐ligand interactions. A limited number of proteases appear to reside in endosomes which do not contain the full complement of active proteases capable of completely DAgrading all internalized polypeptides. Retention of some acid hydrolases in endosomes is apparently related to their association with unDAfined endosomal membrane receptors. The limited number of proteases and the pH gradient from neutral to acidic (pH 7 to 5) within endosomes make possible a selective and controlled processing environment in comparison to lysosomes. The full set of endo‐ and exopeptidases that break down proteins to amino acids are active later in the pathway in lysosomes.