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Structural basis of inactivation of Ras and Rap1 small GTPases by Ras/Rap1-specific endopeptidase from the sepsis-causing pathogen Vibrio vulnificus

Title
Structural basis of inactivation of Ras and Rap1 small GTPases by Ras/Rap1-specific endopeptidase from the sepsis-causing pathogen Vibrio vulnificus
Authors
Jang, Song YeeHwang, JungwonKim, Byoung SikLee, Eun-YoungOh, Byung-HaKim, Myung Hee
Ewha Authors
김병식
Issue Date
2018
Journal Title
JOURNAL OF BIOLOGICAL CHEMISTRY
ISSN
0021-9258JCR Link

1083-351XJCR Link
Citation
JOURNAL OF BIOLOGICAL CHEMISTRY vol. 293, no. 47, pp. 18110 - 18122
Keywords
toxinvirulence factorsepsishost-pathogen interactionbacterial pathogenesiseffectorMARTX toxinRasRap1-specific endopeptidaseVibrio vulnificus
Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Indexed
SCIE; SCOPUS WOS
Document Type
Article
Abstract
Multifunctional autoprocessing repeats-in-toxin (MARTX) toxins are secreted by Gram-negative bacteria and function as primary virulence-promoting macromolecules that deliver multiple cytopathic and cytotoxic effector domains into the host cytoplasm. Among these effectors, Ras/Rap1-specific endopeptidase (RRSP) catalyzes the sequence-specific cleavage of the Switch I region of the cellular substrates Ras and Rap1 that are crucial for host innate immune defenses during infection. To dissect the molecular basis underpinning RRSP-mediated substrate inactivation, we determined the crystal structure of an RRSP from the sepsis-causing bacterial pathogen Vibrio vulnificus (VvRRSP). Structural and biochemical analyses revealed that VvRRSP is a metal-independent TIKI family endopeptidase composed of an N-terminal membrane-localization and substrate-recruitment domain (N lobe) connected via an inter-lobe linker to the C-terminal active site-coordinating core -sheet-containing domain (C lobe). Structure-based mutagenesis identified the 2His/2Glu catalytic residues in the core catalytic domain that are shared with other TIKI family enzymes and that are essential for Ras processing. In vitro KRas cleavage assays disclosed that deleting the N lobe in VvRRSP causes complete loss of enzymatic activity. Endogenous Ras cleavage assays combined with confocal microscopy analysis of HEK293T cells indicated that the N lobe functions both in membrane localization via the first -helix and in substrate assimilation by altering the functional conformation of the C lobe to facilitate recruitment of cellular substrates. Collectively, these results indicate that RRSP is a critical virulence factor that robustly inactivates Ras and Rap1 and augments the pathogenicity of invading bacteria via the combined effects of its N and C lobes.
DOI
10.1074/jbc.RA118.004857
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엘텍공과대학 > 식품공학전공 > Journal papers
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