Moepps B, Vatter P, Frodl R, Waechter F, Dixkens C, Hameister H, Gierschik P. Alternative splicing produces transcripts encoding four variants of mouse G-protein-coupled receptor kinase 6.
Genomics 1999;
60:199-209. [PMID:
10486211 DOI:
10.1006/geno.1999.5901]
[Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A family of protein kinases, termed G-protein-coupled receptor kinases (GRK1-6), is known to phosphorylate agonist-occupied G-protein-coupled receptors. We have identified mRNAs encoding four distinct mouse GRK6 isoforms (mGRK6), designated mGRK6-A through mGRK6-D. Mouse GRK6-B and mGRK6-C diverge from the known human GRK6 (577 residues) at residue 560 and are 13 residues longer and 16 residues shorter, respectively, than human GRK6, while mGRK6-A very likely represents the mouse equivalent of human GRK6. Mouse GRK6-D is identical to the other mGRK6 variants in the amino-terminal region, but comprises only 59 of the 263 amino acids of the putative catalytical domain. As mGRK6-D retains the region involved in interacting with activated receptors, but most likely lacks catalytic activity, this variant might represent a naturally occurring inhibitor of other GRKs. Analysis of the genomic organization of mGRK6 gene revealed that the four mRNAs are generated by alternative RNA splicing from a single approximately 14. 5-kb gene, made up of at least 17 exons and located on mouse chromosome 13. Similar to human GRK6, mGRK6-A contains three cysteine residues within its carboxyl-terminal region known to serve as substrates for palmitoylation. Mouse GRK6-B lacks these palmitoylation sites, but carries a basic carboxyl-terminus containing consensus sequences for phosphorylation by protein kinases C and cAMP/cGMP-dependent protein kinases. Mouse GRK6-C displays none of these motifs. Thus, mGRK6-A, mGRK6-B, and mGRK6-C are predicted to differ in terms of their regulation by carboxyl-terminal posttranslational modification. Analysis of mRNA expression revealed that the four mGRK6 mRNAs are differentially expressed in mouse tissues, suggesting that the four mGRK6 isoforms are involved in regulating tissue- or cell type-specific functions in vivo.
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