This family includes members such as low psii accumulation1 (lpa1) from plants as well as Rep27 proteins found in unicellular green alga Chlamydomonas reinhardtii. The Arabidopsis LPA1 is a chaperone required for efficient photosystem II (PSII) assembly. It binds to psbA during de novo biogenesis of PSII [1]. Other studies show that REP27 in Chlamydomonas reinhardtii chloroplast thylakoids, plays a dual role in the regulation of D1 protein turnover by facilitating cotranslational biosynthesis insertion (C-terminal domain) and activation (tetratricopeptide repeat [TPR] motifs) of the nascent D1 during the PSII repair process [2].

1: LOW PSII ACCUMULATION1 is involved in efficient assembly of photosystem II in Arabidopsis thaliana. Peng L, Ma J, Chi W, Guo J, Zhu S, Lu Q, Lu C, Zhang L; Plant Cell. 2006;18:955-969. PMID:16531500

2: Mechanism of REP27 protein action in the D1 protein turnover and photosystem II repair from photodamage. Dewez D, Park S, Garcia-Cerdan JG, Lindberg P, Melis A; Plant Physiol. 2009;151:88-99. PMID:19574473