title: Site-specific processing of Ras and Rap1 Switch I by a MARTX toxin effector domain.
abstract: Ras (Rat sarcoma) protein is a central regulator of cell growth and proliferation. Mutations in the RAS gene are known to occur in human cancers and have been shown to contribute to carcinogenesis. In this study, we show that the multifunctional-autoprocessing repeats-in-toxin (MARTX) toxin-effector domain DUF5(Vv) from Vibrio vulnificus to be a site-specific endopeptidase that cleaves within the Switch 1 region of Ras and Rap1. DUF5(Vv) processing of Ras, which occurs both biochemically and in mammalian cell culture, inactivates ERK1/2, thereby inhibiting cell proliferation. The ability to cleave Ras and Rap1 is shared by DUF5(Vv) homologues found in other bacteria. In addition, DUF5(Vv )can cleave all Ras isoforms and KRas with mutations commonly implicated in malignancies. Therefore, we speculate that this new family of Ras/Rap1-specific endopeptidases (RRSPs) has potential to inactivate both wild-type and mutant Ras proteins expressed in malignancies.
authors.affiliation: Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Ward 6-225, Chicago, Illinois 60611, USA.
authors.forename: Irena
authors.initials: I
authors.lastname: Antic
authors.affiliation: Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Ward 6-225, Chicago, Illinois 60611, USA.
authors.forename: Marco
authors.initials: M
authors.lastname: Biancucci
authors.affiliation: Department of Radiation Oncology and Pharmacology, Feinberg School of Medicine, Northwestern University, 303 East Superior Avenue, Lurie 3-119, Chicago, Illinois 60611, USA.
authors.forename: Yueming
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Radiation Oncology and Pharmacology, Feinberg School of Medicine, Northwestern University, 303 East Superior Avenue, Lurie 3-119, Chicago, Illinois 60611, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Gius
authors.affiliation: Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Ward 6-225, Chicago, Illinois 60611, USA.
authors.forename: Karla J F
authors.initials: KJF
authors.lastname: Satchell
mesh_terms: D000595:Amino Acid Sequence; D001427:Bacterial Toxins / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D041261:Vibrio vulnificus / Q000378:metabolism*; D020827:rap1 GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D018631:ras Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001427:Bacterial Toxins; C434464:RtxA protein, Vibrio cholerae; D020827:rap1 GTP-Binding Proteins; D018631:ras Proteins