TOC120 is a component of TOC complex, plastid protein import machinery. It functions redundantly with TOC132 in the import of non-photosynthetically-related proteins into plastids. In Arabidopsis thaliana, four psToc159 homologs are identified, termed atToc159(AT4G02510) , atToc132(AT2G16640) , atToc120(AT3G16620) and atToc90( AT5G20300) .
