IN certain plant and yeast proteins, the DnaJ-1 proteins have a three-domain structure. The x-domain lies between the N-terminal DnaJ and the C-terminal Z domains. The exact function is not known.

1: The cytosolic DnaJ-like protein djp1p is involved specifically in peroxisomal protein import. Hettema EH, Ruigrok CC, Koerkamp MG, van den Berg M, Tabak HF, Distel B, Braakman I; J Cell Biol. 1998;142:421-434. PMID:9679141