10779/crick.12683654.v1 Nicole A Gabreski Nicole A Gabreski Janki K Vaghasia Janki K Vaghasia Silvia S Novakova Silvia S Novakova Neil Q McDonald Neil Q McDonald Brian A Pierchala Brian A Pierchala Exon skipping in RET gene encodes novel isoforms that differentially regulate RET protein signal transduction The Francis Crick Institute 2020 alternative splicing cell signaling neurotrophic factor receptor tyrosine kinase signal transduction Animals Exons Humans Isoenzymes Mice NIH 3T3 Cells Phosphorylation Proto-Oncogene Proteins c-ret Rats Signal Transduction Zebrafish Zebrafish Proteins McDonald FC001115 Biochemistry & Molecular Biology 06 Biological Sciences 11 Medical and Health Sciences 03 Chemical Sciences 2020-07-27 11:20:01 Journal contribution https://crick.figshare.com/articles/journal_contribution/Exon_skipping_in_RET_gene_encodes_novel_isoforms_that_differentially_regulate_RET_protein_signal_transduction/12683654 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.