Title: Cloning, sequencing, purification, and Gq-dependent activation of phospholipase C-beta 3. | Journal: The Journal of biological chemistry. 1993 Mar;268(9):6654-61 | Authors: Jhon DY, Lee HH, Park D, Lee CW, Lee KH, Yoo OJ, Rhee SG. | Abstract: Six mammalian phospholipase C isozymes (PLC-beta 1, PLC-beta 2, PLC-gamma 1, PLC-gamma 2, PLC-delta 1, and PLC-delta 2) have been identified at both protein and DNA levels. Here, cDNAs corresponding to a previously unidentified PLC isozyme were isolated from a rat thyroid cell FRTL cDNA library. Comparison of the predicted amino acid sequence of this new PLC with other known PLC isozymes revealed a high degree of overall similarity with PLC-beta 1 and PLC-beta 2. Thus, the new PLC was named PLC-beta 3. Comparison with PLC-beta 1 and PLC-beta 2 also revealed that the deduced amino-terminal sequence of PLC-beta 3 was incomplete by 10-20 amino acids. With the use of antibodies raised against synthetic peptides corresponding to PLC-beta 3-specific amino acid sequences, we purified PLC-beta 3 from a rat brain particulate fraction. The purified enzyme exhibited an apparent molecular mass of 152 kDa on SDS-polyacrylamide gels, as compared with 150 and 140 kDa for PLC-beta 1 and PLC-beta 2, respectively. Studies of the activation of PLC-beta isozymes by three alpha subunits of Gq class G proteins, alpha q, alpha 11, and alpha 16 in the presence of guanosine 5-O-(3-thiotriphosphate) (GTP gamma S) revealed that the extent of activation decreased in the order of PLC-beta 1 > or = PLC-beta 3 >> PLC-beta 2 for all three alpha subunits, suggesting a certain degree of specificity in the interaction of Gq alpha subunits with different PLC-beta isozymes. | See full PubMed entry: http://www.ncbi.nlm.nih.gov/pubmed/8454637 |
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