title: ClpXP and ClpAP proteolytic activity on divisome substrates is differentially regulated following the Caulobacter asymmetric cell division.
abstract: Proteolytic control of Caulobacter cell cycle proteins is primarily executed by ClpXP, a dynamically localized protease implicated in turnover of several factors critical for faithful cell cycle progression. Here, we show that the transient midcell localization of ClpXP that precedes cytokinesis requires the FtsZ component of the divisome. Although ClpAP does not exhibit subcellular localization, FtsZ is a substrate of both ClpXP and ClpAP in vivo and in vitro. A peptide containing the C-terminal portion of the FtsA divisome protein is a substrate of both ClpXP and ClpAP in vitro but is primarily degraded by ClpAP in vivo. Caulobacter carries out an asymmetric division in which FtsZ and FtsA are stable in stalked cells but degraded in the non-replicative swarmer cell where ClpAP alone degrades FtsA and both ClpAP and ClpXP degrade FtsZ. While asymmetric division in Caulobacter normally yields larger stalked and smaller swarmer daughters, we observe a loss of asymmetric size distribution among daughter cells when clpA is depleted from a strain in which FtsZ is constitutively produced. Taken together, these results suggest that the activity of both ClpXP and ClpAP on divisome substrates is differentially regulated in daughter cells.
authors.affiliation: Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
authors.forename: Brandon
authors.initials: B
authors.lastname: Williams
authors.forename: Nowsheen
authors.initials: N
authors.lastname: Bhat
authors.forename: Peter
authors.initials: P
authors.lastname: Chien
authors.forename: Lucy
authors.initials: L
authors.lastname: Shapiro
mesh_terms: D060049:Asymmetric Cell Division; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016934:Caulobacter / Q000737:chemistry / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics; D003598:Cytoskeletal Proteins / Q000378:metabolism; D049071:Endopeptidase Clp / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D059748:Proteolysis; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria; D049071:Endopeptidase Clp