MecA, an adaptor protein necessary for ClpC chaperone activity.
ClpC of Bacillus subtilis is an ATP-dependent HSP100Clp protein involved in general stress survival. A complex of ClpC with the protease ClpP and the adaptor protein MecA also controls competence development by regulated proteolysis of the transcription factor ComK. We investigated the in vitro chaperone activity of ClpC and found that the presence of MecA was crucial for the major chaperone activities of ClpC. In particular, MecA enabled ClpC to solubilize and refold aggregated proteins. Finally, in the presence of ClpP, MecA allowed the ClpC-dependent degradation of unfolded or heat-aggregated proteins. This study demonstrates that adaptor proteins like MecA through interaction with their cognate ClpC proteins can have a dual role in the protein quality-control network by rescuing, or together with ClpP, by degrading, aggregated proteins. MecA can thereby coordinate substrate targeting with ClpC activation, adding another layer to the regulation of HSP100/Clp protein activity.
Schlothauer
Tilman
T
Zentrum für Molekulare Biologie der Universität Heidelberg, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
Mogk
Axel
A
Dougan
David A
DA
Bukau
Bernd
B
Turgay
Kürşad
K
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology; D001412:Bacillus subtilis / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism / Q000502:physiology*; D002364:Caseins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism / Q000502:physiology*; D008156:Luciferases / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D013696:Temperature; D013997:Time Factors
D001426:Bacterial Proteins; D002364:Caseins; C087481:ClpC protein, Bacteria; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; C083616:mecA protein, Bacillus subtilis; D000255:Adenosine Triphosphate; D008291:Malate Dehydrogenase; D008156:Luciferases; D000251:Adenosine Triphosphatases