CLPF is one of the two adaptors (together with CLPS1) that are part of the plastid CLP system. CLPF interacts with chloroplast chaperone CLPC1, which unfolds and delivers substrates to the stromal CLPPRT protease complex for degradation.
FtsH is an essential ATP-dependent metalloprotease for protein quality control in the thylakoid membrane of Arabidopsis thaliana chloroplasts. It is required for chloroplast development during leaf growth, and particularly for the specific degradation of photo-damaged D1 protein in the photosystem II (PSII) complex to maintain photosynthesis activity. In the Arabidopsis thaliana genome, 12 genes encoding members of the FtsH family have been identified. Nine of these proteins (FtsH1, 2, 5, 6, 7, 8, 9, 11, and 12) are located in the chloroplast. FtsH1 and FtsH5 are interchangeable in thylakoid membranes.