DnaJ/HSP40 Homolog Subfamily C, Member 1 (DNAJC1)

DNAJC1 interacted with alpha-1-antichymotrypsin (AACT), and they confirmed the interaction by dot blot, native electrophoresis, and fluorescence studies. The second SANT domain of DNAJC1 (SANT2) was sufficient to bind AACT both in yeast and in vitro, and the interaction was disrupted by a trp520-to-ala mutation in SANT2. AACT bound to SANT2 had no inhibitory activity toward chymotrypsin. SANT2 significantly slowed formation of the AACT-chymotrypsin acyl complex with no significant effect on the catalytic efficiency of chymotrypsin.The deduced 554-amino acid protein has an N-terminal signal sequence, followed by a J domain, a transmembrane region, a ribosome-binding domain, 2 SANT domains, and a C-terminal endoplasmic reticulum retrieval signal.