Molecular cloning of a novel platelet protein showing homology to the angiotensin II receptor C-terminal domain.
Oligoscreening of a cDNA library obtained from 4 beta-phorbol 12-myristate 13-acetate-stimulated human erythroleukemia (HEL) cells resulted in the isolation of a novel clone coding for a protein with a calculated molecular mass of 8110 Da. This protein of 71 amino acids shows significant homology to the carboxyl-terminal regulatory domain of angiotensin II type 1 receptors. The homology encompasses four regions of amino acid residues thought to serve as consensus sequences for phosphorylation by serine/threonine kinases such as protein kinase C, which are key mediators of intracellular signaling. Reverse transcription-polymerase chain reaction identified the transcript in human platelets, human megakaryocytic DAMI cells, and HEL cells. High stringency Northern blotting revealed a tissue-specific distribution of three transcript species, with predominant expression in skeletal muscle and pancreas. Rabbit anti-peptide antiserum was used to immunoblot protein lysates from washed resting platelets and from 4 beta-phorbol 12-myristate 13-acetate-stimulated DAMI and HEL cells. These immunoblots revealed the presence of an intense approximately 8-kDa protein band in platelets and HEL cells and a faint band of identical size in DAMI cells.
Razdan
K
K
Veterans Administration Medical Center, Houston, Texas 77030, USA.
Kroll
M H
MH
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001792:Blood Platelets / Q000737:chemistry*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D015342:DNA Probes / Q000737:chemistry; D015870:Gene Expression; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D011945:Receptors, Angiotensin / Q000737:chemistry*; D016415:Sequence Alignment; D014018:Tissue Distribution
D017931:DNA Primers; D015342:DNA Probes; D008565:Membrane Proteins; D012333:RNA, Messenger; D011945:Receptors, Angiotensin