Part of the inner chloroplast membrane translocon complex (TIC) which associates with the outer chloroplast membrane translocon complex (TOC) and forms a supercomplex involved in protein precursor import into the chloroplast stroma (PubMed:30464337). Required for the import of HSP93, TIC40 and RBCS protein precursors in the chloroplast stroma (PubMed:30464337). Links the outer and inner membrane translocons of the chloroplast envelope (PubMed:30464337). Part of the TIC complex, which can interact with components of the TOC complex to form a larger import complex (PubMed:30464337). Interacts with the TOC complex component TOC75-3 (PubMed:30464337). Embryonic lethality when homozygous (PubMed:15266054). Embryo development arrested at globular stage (PubMed:15266054). Belongs to the TamB family.