INSULIN RECEPTOR-LIKE TYROSINE KINASE IN THE TOBACCO HORNWORM, MANDUCA-SEXTA

Phosphotyrosine-containing proteins are present in the prothoracic gla nds, muscle, and fat body of Manduca sexta, as determined by immunopre cipitation followed by kinase assay, and by Western blotting. One such protein (M-r 178,000) can also be immunoprecipitated using antibodies directed against the human insulin receptor and insulin receptor subs trate. The 178 kD protein appears to be expressed more strongly in pro thoracic glands removed just prior to wandering (days 3-4) and prior t o pupation (days 7-9), and phosphorylation of the protein is enhanced by an M. sexta brain factor. The results suggest that a tyrosine-kinas e-linked molecule similar to the insulin receptor may play a regulator y role in M. sexta. (C) 1997 Wiley-Liss, Inc.