title: Exon Skipping in the RET Gene Encodes Novel Isoforms That Differentially Regulate RET Protein Signal Transduction.
abstract: Rearranged during transfection (RET), a receptor tyrosine kinase that is activated by the glial cell line-derived neurotrophic factor family ligands (GFLs), plays a crucial role in the development and function of the nervous system and additionally is required for kidney development and spermatogenesis. RET encodes a transmembrane receptor that is 20 exons long and produces two known protein isoforms differing in C-terminal amino acid composition, referred to as RET9 and RET51. Studies of human pheochromocytomas identified two additional novel transcripts involving the skipping of exon 3 or exons 3, 4, and 5 and are referred to as RET(Δ) (E3) and RET(Δ) (E345), respectively. Here we report the presence of Ret(Δ) (E3) and Ret(Δ) (E345) in zebrafish, mice, and rats and show that these transcripts are dynamically expressed throughout development of the CNS, peripheral nervous system, and kidneys. We further explore the biochemical properties of these isoforms, demonstrating that, like full-length RET, RET(ΔE3) and RET(ΔE345) are trafficked to the cell surface, interact with all four GFRα co-receptors, and have the ability to heterodimerize with full-length RET. Signaling experiments indicate that RET(ΔE3) is phosphorylated in a similar manner to full-length RET. RET(ΔE345), in contrast, displays higher baseline autophosphorylation, specifically on the catalytic tyrosine, Tyr(905), and also on one of the most important signaling residues, Tyr(1062) These data provide the first evidence for a physiologic role of these isoforms in RET pathway function.
authors.affiliation: From the Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48109, the Program in Cellular and Molecular Biology, University of Michigan School of Medicine, Ann Arbor, Michigan 48109.
authors.forename: Nicole A
authors.initials: NA
authors.lastname: Gabreski
authors.affiliation: From the Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48109.
authors.forename: Janki K
authors.initials: JK
authors.lastname: Vaghasia
authors.affiliation: From the Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48109.
authors.forename: Silvia S
authors.initials: SS
authors.lastname: Novakova
authors.affiliation: the Structural Biology Laboratory, Francis Crick Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, United Kingdom, and the Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, United Kingdom.
authors.forename: Neil Q
authors.initials: NQ
authors.lastname: McDonald
authors.affiliation: From the Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48109, the Program in Cellular and Molecular Biology, University of Michigan School of Medicine, Ann Arbor, Michigan 48109, pierchal@umich.edu.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Pierchala
mesh_terms: D000818:Animals; D005091:Exons; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D051379:Mice; D041681:NIH 3T3 Cells; D010766:Phosphorylation / Q000502:physiology; D051096:Proto-Oncogene Proteins c-ret / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction / Q000502:physiology*; D015027:Zebrafish / Q000235:genetics / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D029961:Zebrafish Proteins; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human; C494999:Ret protein, mouse; C495001:Ret protein, rat; C546313:Ret protein, zebrafish
keywords: alternative splicing; cell signaling; neurotrophic factor; receptor tyrosine kinase; signal transduction