Interacts (via SANT 2 domain) with SERPINA3; the interaction delays the formation of the covalent inhibitory complex SERPINA3-chymotrypsin, but does not alter the catalytic activity of SERPINA3. Interacts (via SANT 2 domain) with ITIH4 (via C-terminus); the interaction protects ITIH4 against in vitro cleavage by kallikrein (By similarity). Interacts (via J domain) with HSPA5. Interacts (via cytosolic domain) with ribosomes.