Small adapter protein that modulate the activity of CLPC (By similarity). Involved in plastid biogenesis in particular when chloroplast protein synthesis capacity is a limiting factor (PubMed:23898032). Probably involved in substrate selection for plastid Clp protease system (PubMed:23898032). Recruitment to ClpC chaperones is facilitated by CLPF thus forming a binary adapter for selective substrate recognition and delivery to plastid Clp protease system (CLPC) (PubMed:26419670). Interacts with CLPC1 (via N-terminus) and CLPC2, but not with CLPt1 or CLPT2 (PubMed:23898032). Binds to ClpF; this interaction stimulates their association with ClpC (PubMed:26419670). Expressed exclusively in photosynthetic green tissues with high levels in young, developing leaf tissues. Not detected in senescing leaves. No visible phenotype (Ref.6, PubMed:23898032). Weak chloroplast phenotype under short-day conditions (PubMed:23898032). Belongs to the ClpS family.