Haloferax volcanii Proteome Response to Deletion of a Rhomboid Protease Gene

MARIANA I. COSTA; MICAELA CERLETTI; ROBERTO A. PAGGI; CHRISTIAN TRÖTSCHEL, ; ROSANA E. DE CASTRO,; ANSGAR POETSCH; MARÍA I. GIMÉNEZ,

JOURNAL OF PROTEOME RESEARCH

AMER CHEMICAL SOC

Año: 2018

1535-3893

ABSTRACT: Rhomboids are conserved intramembrane serine proteasesinvolved in cell signaling processes. Their role in prokaryotes is scarcelyknown and remains to be investigated in Archaea. We previously constructed arhomboid homologue deletion mutant (ΔrhoII) in Haloferax volcanii, whichshowed reduced motility, increased novobiocin sensitivity, and an Nglycosylationdefect. To address the impact of rhoII deletion on H. volcaniiphysiology, the proteomes of mutant and parental strains were compared byshotgun proteomics. A total of 1847 proteins were identified (45.8% of H.volcanii predicted proteome), from which 103 differed in amount. Additionally,the mutant strain evidenced 99 proteins with altered electrophoretic migration,which suggested differential post-translational processing/modification. Integralmembrane proteins that evidenced variations in concentration, electrophoreticmigration, or semitryptic cleavage in the mutant were considered as potentialRhoII targets. These included a PrsW protease homologue (which was lessstable in the mutant strain), a predicted halocyanin, and six integral membrane proteins potentially related to the mutantglycosylation (S-layer glycoprotein, Agl15) and cell adhesion/motility (flagellin1, HVO_1153, PilA1, and PibD) defects. Thisstudy investigated for the first time the impact of a rhomboid protease on the whole proteome of an organism.KEYWORDS: Archaea, Haloferax volcanii, rhomboid protease, shotgun proteomics, protease substrate