Journal Article

genome-wide Drosophila RNAi screen identifies DYRK-family kinases as regulators of NFAT

Srikanth, S, Iuga, A, Hogan, P.G, Bolton, D, Feske, S, Tanasa, B, Sharma, S, Gwack, Y, Nardone, J, Okamura, H

2006

Overview

Precise regulation of the NFAT (nuclear factor of activated T cells) family of transcription factors (NFAT1-4) is essential for vertebrate development and function. In resting cells, NFAT proteins are heavily phosphorylated and reside in the cytoplasm; in cells exposed to stimuli that raise intracellular free Ca2+ levels, they are dephosphorylated by the calmodulin-dependent phosphatase calcineurin and translocate to the nucleus1. NFAT dephosphorylation by calcineurin is countered by distinct NFAT kinases, among them casein kinase 1 (CK1) and glycogen synthase kinase 3 (GSK3). Here we have used a genome-wide RNA interference (RNAi) screen in Drosophila to identify additional regulators of the signalling pathway leading from Ca2+-calcineurin to NFAT. This screen was successful because the pathways regulating NFAT subcellular localization (Ca2+ influx, Ca2+-calmodulin-calcineurin signalling and NFAT kinases) are conserved across species even though Ca2+-regulated NFAT proteins are not themselves represented in invertebrates. Using the screen, we have identified DYRKs (dual-specificity tyrosine-phosphorylation regulated kinases) as novel regulators of NFAT. DYRK1A and DYRK2 counter calcineurin-mediated dephosphorylation of NFAT1 by directly phosphorylating the conserved serine-proline repeat 3 (SP-3) motif of the NFAT regulatory domain, thus priming further phosphorylation of the SP-2 and serine-rich region 1 (SRR-1) motifs by GSK3 and CK1, respectively. Thus, genetic screening in Drosophila can be successfully applied to cross evolutionary boundaries and identify new regulators of a transcription factor that is expressed only in vertebrates.

• Publisher: Nature Publishing Group UK,Nature Publishing,Nature Publishing Group
• Subject: Animals / Biological and medical sciences / Boundaries / calcineurin / calcium / calmodulin / Casein Kinase I - metabolism / Drosophila / Drosophila - enzymology / Drosophila - genetics / Drosophila - metabolism / Drosophila melanogaster / Dyrk Kinases / Enzymes / Evolution / Fundamental and applied biological sciences. Psychology / gene expression regulation / Genes / Genetic aspects / Genetic regulation / Genetic screening / genetic techniques and protocols / Genome, Insect - genetics / Genome-wide association studies / Genomics / Glycogen Synthase Kinase 3 - metabolism / Humanities and Social Sciences / Insects / Interleukin-2 - genetics / Invertebrates / letter / Molecular and cellular biology / Molecular genetics / multidisciplinary / NFATC Transcription Factors - chemistry / NFATC Transcription Factors - metabolism / nuclear factor of activated T cells / Observations / Phosphorylation / Phosphotransferases / Physiological aspects / protein phosphorylation / Protein Serine-Threonine Kinases - classification / Protein Serine-Threonine Kinases - deficiency / Protein Serine-Threonine Kinases - genetics / Protein Serine-Threonine Kinases - metabolism / Protein Structure, Tertiary / Protein-Tyrosine Kinases - classification / Protein-Tyrosine Kinases - deficiency / Protein-Tyrosine Kinases - genetics / Protein-Tyrosine Kinases - metabolism / Proteins / Ribonucleic acid / RNA / RNA Interference / Science / Science (multidisciplinary) / Signal transduction / Transcription factors / Transcription, Genetic - genetics / Transcription. Transcription factor. Splicing. Rna processing / Vertebrates