Clp protease adapter that facilitates CLPS1 recruitment to ClpC chaperones thus forming a binary adapter for selective substrate recognition and delivery to plastid Clp protease system (CLPC). Binds to CLPC1 and CLPC2. Interacts with ClpS1; this interaction stimulates their association with ClpC. Associates with the Clp substrate HEMA1 (GluTR). Expressed constitutively in photosynthetic tissues such as leaves, stems and flowers, and, at low levels, in siliques. Slight reduction during senescence. Reduction by 10 precent of total chlorophyll, with slight increase of chlorophyll a/b ratio and slight decrease of chlorophyll-to-carotenoid ratios. Overaccumulation of ClpS1 protein.