title: Polycystin-1L2 is a novel G-protein-binding protein.
abstract: Mutations in genes encoding polycystin-1 (PC1) and polycystin-2 cause autosomal dominant polycystic kidney disease. The polycystin protein family is composed of Ca2+-permeable pore-forming subunits and receptor-like integral membrane proteins. Here we describe a novel member of the polycystin-1-like subfamily, polycystin-1L2 (PC1L2), encoded by PKD1L2, which has various alternative splicing forms with two translation initiation sites. PC1L2 short form starts in exon 12 of the long form. The longest open reading frame of PKD1L2 short form, determined from human testis cDNA, encodes a 1775-amino-acid protein and 32 exons, whereas the long form is predicted to encode a 2460-residue protein. Both forms have a small receptor for egg jelly domain, a G-protein-coupled receptor proteolytic site, an LH2/PLAT, and 11 putative transmembrane domains, as well as a number of rhodopsin-like G-protein-coupled receptor signatures. RT-PCR analysis shows that the short form, but not the long form, of human PKD1L2 is expressed in the developing and adult heart and kidney. Furthermore, by GST pull-down assay we observed that PC1L2 and polycystin-1L1 are able to bind to specific G-protein subunits. We also show that PC1 C-terminal cytosolic domain binds to Galpha12, Galphas, and Galphai1, while it weakly interacts with Galphai2. Our results indicate that both PC1-like molecules may act as G-protein-coupled receptors.
authors.affiliation: Renal Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yuasa
authors.forename: Ayumi
authors.initials: A
authors.lastname: Takakura
authors.forename: Bradley M
authors.initials: BM
authors.lastname: Denker
authors.forename: Bhuvarahamurthy
authors.initials: B
authors.lastname: Venugopal
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
mesh_terms: D017398:Alternative Splicing / Q000235:genetics* / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009206:Myocardium / Q000378:metabolism*; D009928:Organ Specificity / Q000235:genetics / Q000502:physiology; D016891:Polycystic Kidney, Autosomal Dominant / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000235:genetics / Q000502:physiology; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism*; D016415:Sequence Alignment; D050396:TRPP Cation Channels; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D002118:Calcium; D019204:GTP-Binding Proteins; D008565:Membrane Proteins; D011506:Proteins; D043562:Receptors, G-Protein-Coupled; D050396:TRPP Cation Channels; C496405:PKD1L2 protein, human