The tyrosine kinase McsB is a regulated adaptor protein for ClpCP

Abstract

Cells of the soil bacterium Bacillus subtilis have to adapt to fast environmental changes in their natural habitat. Here, we characterized a novel system in which cells respond to heat shock by regulatory proteolysis of a transcriptional repressor CtsR. In B. subtilis, CtsR controls the synthesis of itself, the tyrosine kinase McsB, its activator McsA and the Hsp100/Clp proteins ClpC, ClpE and their cognate peptidase ClpP. The AAA+ protein family members ClpC and ClpE can form an ATP‐dependent protease complex with ClpP and are part of the B. subtilis protein quality control system. The regulatory response is mediated by a proteolytic switch, which is formed by these proteins under heat‐shock conditions, where the tyrosine kinase McsB acts as a regulated adaptor protein, which in its phosphorylated form activates the Hsp100/Clp protein ClpC and targets the repressor CtsR for degradation by the general protease ClpCP.

Global impact of protein arginine phosphorylation on the physiology of Bacillus subtilis

“…3 A and B). As previously reported (10,20), all ClpC proteins showed very low ATPase activity in the absence of an adaptor protein. When McsB and its activator McsA were added to the assay, the ATPase activity of wild-type ClpC was fully induced.…”

“…In contrast to other Hsp100/Clp proteins, ClpC activity depends on the assistance of specific adaptor proteins (18). These adaptor proteins include MecA, which targets ComK for ClpCP-dependent degradation (19), and McsB, which in its kinase-active form targets CtsR for ClpCP-mediated degradation (10,20).…”

“…DNA manipulation and other molecular biological procedures were carried out according to standard protocols. The biochemical assays were performed as previously described (9,10). For details of MS, protein digestion, phosphopeptide enrichment, and identification of phosphate-containing peptides, see SI Materials and Methods.…”

Degradation of SsrA-tagged proteins in streptococci

“…However, several adaptor proteins for ClpC have SsrA-tagged proteins in streptococci been identified in Gram-positive bacteria, including MecA, McsB, NblA, YpbH and TrfA (Andersson et al, 2006;Donegan et al, 2014;Karradt et al, 2008;Kirstein et al, 2007;Persuh et al, 2002;Turgay et al, 1998). All known ClpC activities require the participation of an adaptor protein (Kirstein et al, 2007(Kirstein et al, , 2009Schlothauer et al, 2003;Turgay et al, 1998;Wang et al, 2011). For example, TrfA is required for the degradation of SsrA-tagged proteins in S. aureus (Donegan et al, 2014).…”

Bacterial Protein-Tyrosine Kinases

“…By consequence, the tyrosinephosphorylated CtsR was reported to release its target DNA. McsB was also found to act as a regulated adaptor protein for ClpCP, the protease complex responsible for the degradation of CtsR [32]. The active, phosphorylated kinase McsB interacts with both CtsR and ClpC, and targets CtsR to the ClpCP complex.…”