Journal Article

Arginine phosphorylation marks proteins for degradation by a Clp protease

Heuck, Alexander, Clausen, Tim, Trentini, Débora Broch, Mechtler, Karl, Suskiewicz, Marcin Józef, Deszcz, Luiza, Kurzbauer, Robert

2016

Overview

Protein turnover is a tightly controlled process that is crucial for the removal of aberrant polypeptides and for cellular signalling. Whereas ubiquitin marks eukaryotic proteins for proteasomal degradation, a general tagging system for the equivalent bacterial Clp proteases is not known. Here we describe the targeting mechanism of the ClpC–ClpP proteolytic complex from Bacillus subtilis . Quantitative affinity proteomics using a ClpP-trapping mutant show that proteins phosphorylated on arginine residues are selectively targeted to ClpC–ClpP. In vitro reconstitution experiments demonstrate that arginine phosphorylation by the McsB kinase is required and sufficient for the degradation of substrate proteins. The docking site for phosphoarginine is located in the amino-terminal domain of the ClpC ATPase, as resolved at high resolution in a co-crystal structure. Together, our data demonstrate that phosphoarginine functions as a bona fide degradation tag for the ClpC–ClpP protease. This system, which is widely distributed across Gram-positive bacteria, is functionally analogous to the eukaryotic ubiquitin–proteasome system. In Gram-positive bacteria, arginine phosphorylation by the McsB kinase functions as a general post-translational marker for Clp-mediated proteolysis. Degradation signal for the ClpC–ClpP proteolytic complex Protein ubiquitination can mark proteins for degradation by the proteasome in eukaryotic cells, but it is unknown whether such a tagging system for the equivalent bacterial Clp proteases exists. Here, Tim Clausen and colleagues report that arginine phosphorylation by the McsB kinase functions as a general post-translational marker for proteasomal degradation in Gram-positive bacteria, tagging at least 25% of all proteins degraded by Clp. The phosphoarginine degradation pathway is essential to cope with proteotoxic stress in vivo .

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 631/326/41 / 631/45/468 / 631/45/612/1246 / Adenosine Triphosphatases - chemistry / Adenosine Triphosphatases - genetics / Adenosine Triphosphatases - metabolism / Arginine / Arginine - analogs & derivatives / Arginine - metabolism / ATPases / Bacillus subtilis - enzymology / Bacteria / Bacterial Proteins - metabolism / Binding Sites / Crystallography, X-Ray / Endopeptidase Clp - chemistry / Endopeptidase Clp - genetics / Endopeptidase Clp - metabolism / Gram-positive bacteria / Humanities and Social Sciences / Kinases / multidisciplinary / Mutation / Observations / Organophosphorus Compounds - metabolism / Phosphatase / Phosphorylation / Physiological aspects / Proteases / Protein folding / Protein Kinases - metabolism / Proteins / Proteolysis / Science