Identification of cDNA encoding an additional alpha subunit of a human GTP-binding protein: expression of three alpha i subtypes in human tissues and cell lines
| Autor: | Yasuhiro Kawahara, Richard T. Lee, Kenneth D. Bloch, Eva J. Neer, Daniel Bloch, Jonathan G. Seidman, Cynthia Tolman, Siew-Lan Ang, Sunyoung Kim |
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| Rok vydání: | 1988 |
| Předmět: |
Multidisciplinary
Base Sequence Macromolecular Substances G protein Molecular Sequence Data Interleukin 5 receptor alpha subunit Gi alpha subunit Alpha (ethology) DNA Biology Molecular biology Cell Line Interleukin 10 receptor alpha subunit SCN3A Genes Biochemistry GTP-Binding Proteins G12/G13 alpha subunits Humans Amino Acid Sequence Cloning Molecular Research Article G alpha subunit |
| Zdroj: | Proceedings of the National Academy of Sciences. 85:4153-4157 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.85.12.4153 |
| Popis: | The guanine nucleotide-binding proteins (G proteins), which mediate hormonal regulation of many membrane functions, are composed of alpha, beta, and gamma subunits. We have cloned and characterized cDNA from a human T-cell library encoding a form of alpha i that is different from the human alpha i subtypes previously reported [Didsbury, J. R., Ho, Y.-S. & Snyderman, R. (1987) FEBS Lett. 211, 160-164 and Bray, P., Carter, A., Guo, V., Puckett, C., Kamholz, J., Spiegel, A. & Nirenberg, M. (1987) Proc. Natl. Acad. Sci. USA 84, 5115-5119]. alpha i is the alpha subunit of a class of G proteins that inhibits adenylate cyclase and regulates other enzymes and ion channels. This cDNA encodes a polypeptide of 354 amino acids and is assigned to encode the alpha i-3 subtype of G proteins on the basis of its similarity to other alpha i-like cDNAs and the presence of a predicted site for ADP ribosylation by pertussis toxin. We have determined the expression of mRNA for this and two other subtypes of human alpha i (alpha i-1 and alpha i-2) in a variety of human fetal tissues and in human cell lines. All three alpha i subtypes were present in the tissues tested. However, analysis of individual cell types reveals specificity of alpha i-1 expression. mRNA for alpha i-1 is absent in T cells, B cells, and monocytes but is present in other cell lines. The finding of differential expression of alpha i-1 genes may permit characterization of distinct physiological roles for this alpha i subunit. mRNA for alpha i-2 and alpha i-3 was found in all the primary and transformed cell lines tested. Thus, some cells contain all three alpha i subtypes. This observation raises the question of how cells prevent cross talk among receptors that are coupled to effectors through such similar alpha proteins. |
| Databáze: | OpenAIRE |
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