The DICE-binding activity of KH domain 3 of hnRNP K is affected by c-Src-mediated tyrosine phosphorylation.
hnRNP K and hnRNP E1/E2 are RNA-binding proteins comprised of three hnRNP K-homology (KH) domains. These proteins are involved in the translational control and stabilization of mRNAs in erythroid cells. hnRNP E1 and hnRNP K regulate the translation of reticulocyte 15-lipoxygenase (r15-LOX) mRNA. Both proteins bind specifically to the differentiation control element (DICE) in the 3' untranslated region (3'UTR) of the r15-LOX mRNA. It has been shown that hnRNP K is a substrate of the tyrosine kinase c-Src and that tyrosine phosphorylation by c-Src inhibits the binding of hnRNP K to the DICE. Here, we investigate which of the three KH domains of hnRNP E1 and hnRNP K mediate the DICE interaction. Using RNA-binding assays, we demonstrate DICE-binding of the KH domains 1 and 3 of hnRNP E1, and KH domain 3 of hnRNP K. Furthermore, with RNA-binding assays, NMR experiments and in vitro translation studies, we show that tyrosine 458 in KH domain 3 of hnRNP K is important for the DICE interaction and we provide evidence that it is a target of c-Src.
Messias
Ana C
AC
Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstr. 1, 69117 Heidelberg, Germany.
Harnisch
Christiane
C
Ostareck-Lederer
Antje
A
Sattler
Michael
M
Ostareck
Dirk H
DH
D020413:3' Untranslated Regions; D000595:Amino Acid Sequence; D001093:Arachidonate 15-Lipoxygenase / Q000737:chemistry; D000081247:CSK Tyrosine-Protein Kinase; D034641:Heterogeneous-Nuclear Ribonucleoprotein K / Q000737:chemistry; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000737:chemistry*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000737:chemistry*; D012045:Regulatory Sequences, Nucleic Acid; D014158:Transcription, Genetic; D014443:Tyrosine / Q000737:chemistry*; D019061:src-Family Kinases
D020413:3' Untranslated Regions; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D014443:Tyrosine; D001093:Arachidonate 15-Lipoxygenase; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human