title: Filamentous actin is a substrate for protealysin, a metalloprotease of invasive Serratia proteamaculans.
abstract: Homologous bacterial metalloproteases ECP32/grimelysin from Serratia grimesii and protealysin from Serratia proteamaculans are involved in the invasion of the nonpathogenic bacteria in eukaryotic cells and are suggested to translocate into the cytoplasm [Bozhokina ES et al. (2011) Cell Biol Int35, 111-118]. The proteases have been characterized as actin-hydrolyzing enzymes with a narrow specificity toward intact cell proteins. However, cleavage of filamentous actin (F-actin) (i.e. the main actin species in the cell) and the properties of the cleaved F-actin have not been investigated previously. In the present study, we revealed the presence of protealysin in the cytoplasm of 3T3-SV40 cells infected with S. proteamaculans or recombinant Escherichia coli expressing the protealysin gene. We also show for the first time that purified protealysin and the lysates of the recombinant E. coli producing protealysin cleave 20-40% of F-actin. Cleavage limited predominantly to the bond Gly42-Val43 efficiently increases the steady-state ATPase activity (dynamics) of F-actin. abolishes this effect and promotes the nucleation of protealysin-cleaved Mg-globular-actin even in the absence of 0.1 m KCl, most likely as a result of the stabilization of lateral intermonomer contacts of actin subunits. The results obtained in the present study suggest that F-actin can be a target for protealysin upon its translocation into the host cell.
authors.affiliation: Institute of Cytology, RAS, St Petersburg, Russia.
authors.forename: Olga
authors.initials: O
authors.lastname: Tsaplina
authors.forename: Tatiana
authors.initials: T
authors.lastname: Efremova
authors.forename: Ilya
authors.initials: I
authors.lastname: Demidyuk
authors.forename: Sofia
authors.initials: S
authors.lastname: Khaitlina
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D000199:Actins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D041702:BALB 3T3 Cells; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000378:metabolism / Q000472:pathogenicity / Q000648:ultrastructure; D005347:Fibroblasts / Q000378:metabolism / Q000382:microbiology / Q000648:ultrastructure; D008666:Metalloendopeptidases / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008970:Molecular Weight; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D055550:Protein Stability / Q000187:drug effects; D021381:Protein Transport; D059748:Proteolysis / Q000187:drug effects; D011817:Rabbits; D011994:Recombinant Proteins / Q000378:metabolism; D012705:Serratia / Q000201:enzymology* / Q000378:metabolism / Q000472:pathogenicity; D013379:Substrate Specificity
chemical_list: D000199:Actins; D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D010446:Peptide Fragments; D011994:Recombinant Proteins; D008666:Metalloendopeptidases; D000251:Adenosine Triphosphatases