Characterization of insulin receptor from the muscle of the shrimp Penaeus japonicus (Crustacea: Decapoda).

The beta-subunit of the insulin receptor from the muscle of the shrimp Penaeus japonicus exists as multiple subtypes with M(r) of 79,000, 77,000 and 75,000. Only the subunit of M(r) 79,000 is autophosphorylated after the addition of insulin. The autophosphorylation occurred specifically at Tyr residues, as demonstrated by the specific subsequent dephosphorylation by the phosphotyrosyl protein phosphatase from the human placenta. The detergent, Triton X-100, and the metal ion, Mn2+, caused a noticeable enhancement of the autophosphorylation of shrimp insulin receptors from the muscle. Okadaic acid activated the kinase activity of the insulin-stimulated insulin receptor, but not the basal activity of the insulin receptor without the addition of insulin. Further studies comparing the insulin binding of the shrimp insulin receptor in the regulation of kinase activity of the multiple beta-subunit subtypes from the shrimp muscle are under way.