ClpCP

ClpCP refers to a proteolytic system formed by the ClpP protease core and the ClpC ATPase chaperone. In many bacteria and in some organelles, ClpP provides the proteolytic core, while ClpC uses ATP hydrolysis to recognize, unfold, and translocate substrates into ClpP for degradation. The overall activity of ClpCP is driven by energy from ATP and is tightly regulated by adaptor proteins that determine which proteins are delivered to the complex.

Substrate recognition often relies on adaptor proteins that bind specific targets and present them to the ClpC–ClpP complex. In Bacillus subtilis, for example, MecA acts as an adaptor, binding substrates such as the transcription factor ComK and directing their degradation by ClpC–ClpP, thereby influencing competence development. Additional adaptors and regulatory signals modulate ClpCP activity in response to stress, growth phase, and cellular needs, enabling selective proteolysis.

Distribution and significance: ClpCP-type proteases are widespread in bacteria, particularly among Gram-positive species. In eukaryotic organelles, such as mitochondria and chloroplasts, ClpP collaborates with ClpC-like ATPases to form analogous proteolytic complexes used in regulated proteolysis and protein quality control.

Function and role: ClpCP contributes to protein quality control by removing misfolded or damaged proteins and to the regulated proteolysis of regulatory proteins, supporting rapid cellular adaptation to environmental changes. It complements other Clp proteases, such as ClpXP and ClpAP, by targeting a distinct set of substrates.