7z27
Crystal structure of the SPOC domain of human RBM15
Structural highlights
DiseaseRBM15_HUMAN Megakaryoblastic acute myeloid leukemia with t(1;22)(p13;q13). A chromosomal aberration involving RBM15 may be a cause of acute megakaryoblastic leukemia. Translocation t(1;22)(p13;q13) with MKL1. Although both reciprocal fusion transcripts are detected in acute megakaryoblastic leukemia (AMKL, FAB-M7), the RBM15-MKL1 chimeric protein has all the putative functional domains encoded by each gene and is the candidate oncogene.[1] [2] FunctionRBM15_HUMAN RNA-binding protein that acts as a key regulator of N6-methyladenosine (m6A) methylation of RNAs, thereby regulating different processes, such as hematopoietic cell homeostasis, alternative splicing of mRNAs and X chromosome inactivation mediated by Xist RNA (PubMed:27602518). Associated component of the WMM complex, a complex that mediates N6-methyladenosine (m6A) methylation of RNAs, a modification that plays a role in the efficiency of mRNA splicing and RNA processing (By similarity). Plays a key role in m6A methylation, possibly by binding target RNAs and recruiting the WMM complex (PubMed:27602518). Involved in random X inactivation mediated by Xist RNA: acts by binding Xist RNA and recruiting the WMM complex, which mediates m6A methylation, leading to target YTHDC1 reader on Xist RNA and promoting transcription repression activity of Xist (PubMed:27602518). Required for the development of multiple tissues, such as the maintenance of the homeostasis of long-term hematopoietic stem cells and for megakaryocyte (MK) and B-cell differentiation (By similarity). Regulates megakaryocyte differentiation by regulating alternative splicing of genes important for megakaryocyte differentiation; probably regulates alternative splicing via m6A regulation (PubMed:26575292). Required for placental vascular branching morphogenesis and embryonic development of the heart and spleen (By similarity). Acts as a regulator of thrombopoietin response in hematopoietic stem cells by regulating alternative splicing of MPL (By similarity). May also function as an mRNA export factor, stimulating export and expression of RTE-containing mRNAs which are present in many retrotransposons that require to be exported prior to splicing (PubMed:17001072, PubMed:19786495). High affinity binding of pre-mRNA to RBM15 may allow targeting of the mRNP to the export helicase DBP5 in a manner that is independent of splicing-mediated NXF1 deposition, resulting in export prior to splicing (PubMed:17001072, PubMed:19786495). May be implicated in HOX gene regulation (PubMed:11344311).[UniProtKB:Q0VBL3][3] [4] [5] [6] [7] Publication Abstract from PubMedThe heptad repeats of the C-terminal domain (CTD) of RNA polymerase II (Pol II) are extensively modified throughout the transcription cycle. The CTD coordinates RNA synthesis and processing by recruiting transcription regulators as well as RNA capping, splicing and 3'end processing factors. The SPOC domain of PHF3 was recently identified as a CTD reader domain specifically binding to phosphorylated serine-2 residues in adjacent CTD repeats. Here, we establish the SPOC domains of the human proteins DIDO, SHARP (also known as SPEN) and RBM15 as phosphoserine binding modules that can act as CTD readers but also recognize other phosphorylated binding partners. We report the crystal structure of SHARP SPOC in complex with CTD and identify the molecular determinants for its specific binding to phosphorylated serine-5. PHF3 and DIDO SPOC domains preferentially interact with the Pol II elongation complex, while RBM15 and SHARP SPOC domains engage with writers and readers of m(6)A, the most abundant RNA modification. RBM15 positively regulates m(6)A levels and mRNA stability in a SPOC-dependent manner, while SHARP SPOC is essential for its localization to inactive X-chromosomes. Our findings suggest that the SPOC domain is a major interface between the transcription machinery and regulators of transcription and co-transcriptional processes. The SPOC domain is a phosphoserine binding module that bridges transcription machinery with co- and post-transcriptional regulators.,Appel LM, Franke V, Benedum J, Grishkovskaya I, Strobl X, Polyansky A, Ammann G, Platzer S, Neudolt A, Wunder A, Walch L, Kaiser S, Zagrovic B, Djinovic-Carugo K, Akalin A, Slade D Nat Commun. 2023 Jan 11;14(1):166. doi: 10.1038/s41467-023-35853-1. PMID:36631525[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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