title: Colocalization of calcium-dependent protease II and one of its substrates at sites of cell adhesion.
abstract: Adhesion plaques, specialized regions of the plasma membrane where a cell contacts its substratum, are dynamic structures. However, little is known about how the protein-protein interactions that occur at adhesion plaques are controlled. One mechanism by which a cell might modulate its associations with the substratum is by selective, regulated proteolysis of an adhesion plaque component. Here we show that the catalytic subunit of the calcium-dependent protease type II (CDP-II) is localized in adhesion plaques of several cell types (BS-C-1, EBTr, and MDBK). We have compared the susceptibility of the adhesion plaque constituents vinculin, talin, and alpha-actinin to calcium-dependent proteolysis in vitro and have found talin to be the preferred substrate for CDP-II. The colocalization of a calcium-requiring proteolytic enzyme and talin in adhesion plaques raises the possibility that calcium-dependent proteolytic activity provides a mechanism for regulating some aspect of adhesion plaque physiology and function via cleavage of talin.
authors.affiliation: Department of Biology, University of Utah, Salt Lake City 84112.
authors.forename: M C
authors.initials: MC
authors.lastname: Beckerle
authors.forename: K
authors.initials: K
authors.lastname: Burridge
authors.forename: G N
authors.initials: GN
authors.lastname: DeMartino
authors.forename: D E
authors.initials: DE
authors.lastname: Croall
mesh_terms: D000185:Actinin / Q000378:metabolism; D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism; D002154:Calpain / Q000032:analysis*; D002417:Cattle; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules; D002460:Cell Line; D002522:Chlorocebus aethiops; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D007668:Kidney / Q000166:cytology; D009124:Muscle Proteins / Q000378:metabolism; D016608:Talin; D016596:Vinculin
chemical_list: D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D009124:Muscle Proteins; D016608:Talin; D000185:Actinin; D016596:Vinculin; D002154:Calpain