An essential signal peptide peptidase identified in an RNAi screen of serine peptidases of Trypanosoma brucei

Moss, C. X., Brown, E., Hamilton, A., Van der Veken, P., Augustyns, K. and Mottram, J. (2015) An essential signal peptide peptidase identified in an RNAi screen of serine peptidases of Trypanosoma brucei. PLoS ONE, 10(3), e0123241. (doi:10.1371/journal.pone.0123241) (PMID:25816352) (PMCID:PMC4376731)

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Abstract

The serine peptidases of Trypanosoma brucei have been viewed as potential drug targets. In particular, the S9 prolyl oligopeptidase subfamily is thought to be a good avenue for drug discovery. This is based on the finding that some S9 peptidases are secreted and active in the mammalian bloodstream, and that they are a class of enzyme against which drugs have successfully been developed. We collated a list of all serine peptidases in T. brucei, identifying 20 serine peptidase genes, of which nine are S9 peptidases. We screened all 20 serine peptidases by RNAi to determine which, if any, are essential for bloodstream form T. brucei survival. All S9 serine peptidases were dispensable for parasite survival in vitro, even when pairs of similar genes, coding for oligopeptidase B or prolyl oligopeptidase, were targeted simultaneously. We also found no effect on parasite survival in an animal host when the S9 peptidases oligopeptidase B, prolyl oligopeptidase or dipeptidyl peptidase 8 were targeted. The only serine peptidase to emerge from the RNAi screen as essential was a putative type-I signal peptide peptidase (SPP1). This gene was essential for parasite survival both in vitro and in vivo. The growth defect conferred by RNAi depletion of SPP1 was rescued by expression of a functional peptidase from an RNAi resistant SPP1 gene. However, expression of catalytically inactive SPP1 was unable to rescue cells from the SPP1 depleted phenotype, demonstrating that SPP1 serine peptidase activity is necessary for T. brucei survival.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Brown, Miss Elaine and Hamilton, Mrs Alana and Mottram, Professor Jeremy
Authors: Moss, C. X., Brown, E., Hamilton, A., Van der Veken, P., Augustyns, K., and Mottram, J.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:PLoS ONE
Publisher:Public Library of Science
ISSN:1932-6203
Copyright Holders:Copyright © 2015 The Authors
First Published:First published in PLoS ONE 10(3):e0123241
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
454141Analysing the roles of petidases in Leishmania infectivity and pathogenicityJeremy MottramMedical Research Council (MRC)G0700127III - PARASITOLOGY
485433Serine peptidases of Trypanosoma brucei as drug targetsCatherine MossWellcome Trust (WELLCOME)091117/Z/10/ZIII - PARASITOLOGY
371796The Wellcome Centre for Molecular Parasitology ( Core Support )Andrew WatersWellcome Trust (WELLCOME)085349/Z/08/ZIII - PARASITOLOGY
371798The Wellcome Centre for Molecular Parasitology ( Core Support )Andrew WatersWellcome Trust (WELLCOME)085349/B/08/ZIII - PARASITOLOGY