Abstract
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.
Highlights
Cell growth and function are regulated through the action of a variety of extracellular ligands binding to specific receptors, initiating intracellular signaling mediated by sequentially activated protein kinases
Serine/threonine kinases such as protein kinase C are critically important enzymes modulating cellular function [1]
All AT1 receptors and the amphibian Angiotensin II (AII) receptors have several Ser/Thr residues in the carboxyl-terminal cytoplasmic tail that may serve as substrates for phosphorylation by protein kinase C [14]
Summary
Vol 271, No 4, Issue of January 26, pp. 2221–2224, 1996 Printed in U.S.A. Molecular Cloning of a Novel Platelet Protein Showing Homology to the Angiotensin II Receptor C-terminal Domain*. This report describes the isolation of a novel cDNA clone coding for a protein with a calculated molecular mass of 8110 Da. This report describes the isolation of a novel cDNA clone coding for a protein with a calculated molecular mass of 8110 Da This protein shows significant homology to the regulatory C-terminal domains of the amphibian AII and mammalian AT1 receptors (59 and 45%, respectively, over a 40-amino acid stretch). This homology includes four consensus protein kinase C phosphorylation sites and a receptor internalization signal [14, 15]. Immunoblotting with an anti-peptide antiserum demonstrates that the native protein is expressed in human platelets and cultured cells of human megakaryocytic lineage
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
