Platelet cytosolic 44-kDa protein is a substrate of cholera toxin-induced ADP-ribosylation and is not recognized by antisera against the. alpha. subunit of the stimulatory guanine nucleotide-binding regulatory protein

Journal Article · Mon Aug 01 00:00:00 EDT 1988 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.85.16.5899· OSTI ID:5641944

Molina Y Vedia, L M; Reep, B R; Lapetina, E G ^[1]

---

1. Burroughs Wellcome Co., Research Triangle Park, NC (USA)

ADP-ribosylation induced by cholera toxin and pertussis toxin was studied in particulate and cytosolic fractions of human platelets. Platelets were disrupted by a cycle of freezing and thawing in the presence of a hyposmotic buffer containing protease inhibitors. In both fractions, the A subunit of cholera toxin ADP-ribosylates two proteins with molecular masses of 42 and 44 kDa, whereas pertussis toxin ADP-ribosylates a 41-kDa polypeptide. Two antisera against the {alpha} subunit of the stimulatory guanine nucleotide-binding regulatory protein recognize only the 42-kDa polypeptide. Cholera toxin-induced ADP-ribosylation of the 42- and 44-kDa proteins is reduced by pretreatment of platelets with iloprost, a prostacyclin analog. The 44-kDa protein, which is substrate of cholera toxin, could be extracted completely from the membrane and recovered in the cytosolic fraction when the cells were disrupted by Dounce homogenization and the pellet was extensively washed. A 44-kDa protein can also be labeled with 8-azidoguanosine 5{prime}-({alpha}-{sup 32}P)triphosphate in the cytosol and membranes. These finding indicate that cholera and pertussis toxins produced covalent modifications of proteins present in particulate and cytosolic platelet fractions. Moreover, the 44-kDa protein might be an {alpha} subunit of a guanine nucleotide-binding regulatory protein that is not recognized by available antisera.

• OSTI ID: 5641944
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 85:16; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADP
ALDEHYDES
AMINES
ANIMALS
ANTIGENS
AROMATICS
AUTORADIOGRAPHY
AZAARENES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD PLATELETS
BODY FLUIDS
CARBOHYDRATES
CHEMISTRY
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
GUANINE
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
IMMUNE SERUMS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAMMALS
MAN
MATERIALS
MEMBRANE PROTEINS
MOLECULAR STRUCTURE
MONOSACCHARIDES
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PENTOSES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PRIMATES
PROTEINS
PURINES
RADIOISOTOPES
RECEPTORS
RIBOSE
SACCHARIDES
SUBSTRATES
TOXIC MATERIALS
TOXINS
VERTEBRATES