Polypeptide hormones and chromatin-associated proteins act as acceptors for cholera toxin-catalyzed ADP-ribosylation.
Cholera toxin catalyzed the ADP-ribosylation of the pituitary protein hormones thyrotropin (TSH), lutropin (LH), follitropin (FSH), human chorionic gonadotropin (hCG), and corticotropin (ACTH)1-24, and ADP-ribosylation of the basic proteins histone subfraction H1 and protamine. Casein and phosvitin, acidic nuclear proteins, did not act as acceptors for toxin-catalyzed ADP-ribosylation. The isolated TSH A and B subunits were tested for their ADP-ribose acceptor activity. The TSH A subunit showed fourfold greater ADP-ribose acceptor activity than the TSH B subunit. The ADP-ribose acceptor protein protamine was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis following incubation with cholera toxin under ADP-ribosylating conditions. [3H]ADP-ribose incorporated into protein from [3H]NAD migrated with the acceptor protein protamine. In the absence of added acceptor protein, the [3H]ADP-ribose incorporated into protein migrated with the A1 fragment of cholera toxin. Cholera toxin A and B subunits were isolated and tested for their ability to catalyze the transfer of ADP-ribose to protamine. The cholera toxin A subunit showed 50-fold greater ADP-ribosyltransferase activity than the B subunit. Our data indicate that a variety of adenohypophyseal hormones and regulatory proteins act as acceptors for toxin-catalyzed ADP-ribosylation. These studies may help in understanding the role of endogenous ADP-ribosyltransferases and the physiological effects of this modification of protein.
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D002772:Cholera Toxin / Q000494:pharmacology*; D006063:Chorionic Gonadotropin / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D006657:Histones / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000378:metabolism; D009702:Nucleoside Diphosphate Sugars / Q000378:metabolism*; D010774:Phosvitin / Q000378:metabolism; D010907:Pituitary Hormones / Q000378:metabolism*; D011479:Protamines / Q000378:metabolism*; D013972:Thyrotropin / Q000378:metabolism
D006063:Chorionic Gonadotropin; D002843:Chromatin; D006657:Histones; D009702:Nucleoside Diphosphate Sugars; D010907:Pituitary Hormones; D011479:Protamines; D000246:Adenosine Diphosphate Ribose; D000324:Adrenocorticotropic Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013972:Thyrotropin; D010774:Phosvitin; D002772:Cholera Toxin