DDX3 a multifunctional DEAD box family RNA helicase with diverse cellular functions. DEAD box proteins are characterized by the conserved motif Asp-Glu-Ala-Asp (DEAD), and are involved in several steps of gene expression, such as transcription, maturation of nuclear and mitochondrial mRNA, mRNA export, translation initiation, and ribosome and spliceosome assembly. DDX3 is required for nuclear export of HIV-1 viral transcripts, possibly in a complex with the viral Rev protein and host cofactor CRM1. DDX3 is required for hepatitis C virus (HCV) RNA replication and its expression is downregulated in hepatitis B virus (HBV) associated hepatocellular carcinoma (HCC). May function as a tumor suppressor protein. Its expression inhibits tumor cell colony formation and increases expression of the cdk inhibitor p21 Waf1/Cip1. Low DDX3 expression has been shown in HCC, and aberrant subcellular localization occurs in many squamous cell carcinomas. Reduced DDX3 expression in cultured cells causes a diminished dependence on serum for cell proliferation and changes in cyclin D1 and p21 Waf1/Cip1 expression. Associates with eIF4F to promote translation of selected mRNAs. Is phosphorylated by the mitotic cyclin dependent kinase, cyclin B/cdc2. This phosphorylation may cause a loss of DDX3 function and a concomitant repression of ribosome biogenesis and translation in mitosis. Involved in TBK1 and IKBKE-dependent IRF3 activation leading to IFN-beta induction. Involved in regulation of apoptosis. May be required for activation of the intrinsic but inhibit activation of the extrinsic apoptotic pathway. Regulated by the cell cycle. Maximally expressed in the cytoplasm during G1/S phase and decreased expression during G2/M phase. Located predominantly in nuclear speckles and, at low levels, throughout the cytoplasm. Associates with the outer side of nuclear pore complexes (NPC) and mitochondrial outer membranes. Shuttles between the nucleus and the cytoplasm in an exportin1-dependent manner. Associates with polyadenylated mRNAs in the cytoplasm and the nucleus. Predominantly located in nucleus during G0 phase and in the cytoplasm during G1/S phase. Belongs to the DEAD box helicase family, DDX3 subfamily. Two isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.
Protein type: Cell cycle regulation; EC 3.6.4.13; Helicase; RNA-binding; Spliceosome; Translation initiation
Chromosomal Location of Human Ortholog: X A1.1|X 8.17 cM
Cellular Component:  cytoplasm; cytoplasmic stress granule; cytosol; membrane; mitochondrial outer membrane; mitochondrion; nucleus
Molecular Function:  ATP binding; ATP-dependent DNA helicase activity; ATP-dependent RNA helicase activity; ATPase activity; CTPase activity; DNA binding; eukaryotic initiation factor 4E binding; GTPase activity; helicase activity; hydrolase activity; mRNA 5'-UTR binding; nucleic acid binding; nucleoside-triphosphatase activity; nucleotide binding; poly(A) binding; protein binding; protein serine/threonine kinase activator activity; ribosomal small subunit binding; RNA binding; RNA stem-loop binding; RNA strand annealing activity; transcription factor binding; translation initiation factor binding
Biological Process:  apoptotic process; cellular response to arsenic-containing substance; cellular response to osmotic stress; chromosome segregation; extrinsic apoptotic signaling pathway via death domain receptors; immune system process; innate immune response; intracellular signal transduction; intrinsic apoptotic signaling pathway; mature ribosome assembly; negative regulation of apoptotic process; negative regulation of cell growth; negative regulation of cysteine-type endopeptidase activity involved in apoptotic process; negative regulation of intrinsic apoptotic signaling pathway; negative regulation of protein complex assembly; negative regulation of translation; positive regulation of apoptotic process; positive regulation of canonical Wnt signaling pathway; positive regulation of cell growth; positive regulation of cysteine-type endopeptidase activity involved in apoptotic process; positive regulation of G1/S transition of mitotic cell cycle; positive regulation of gene expression; positive regulation of protein serine/threonine kinase activity; positive regulation of transcription by RNA polymerase II; positive regulation of translation; positive regulation of translational initiation; positive regulation of viral genome replication; protein localization to cytoplasmic stress granule; regulation of translation; response to virus; ribosome biogenesis; RNA secondary structure unwinding; stress granule assembly; translational initiation; Wnt signaling pathway
Reference #:  Q62167 (UniProtKB)
Alt. Names/Synonyms: ATP-dependent RNA helicase DDX3X; D-E-A-D (aspartate-glutamate-alanine-aspartate) box polypeptide 3; D1Pas1-related sequence 2; D1Pas1-rs2; Ddx3; Ddx3x; DEAD (aspartate-glutamate-alanine-aspartate) box polypeptide 3; DEAD box protein 3, X-chromosomal; DEAD box RNA helicase DEAD3; DEAD-box protein 3 (DEAD-box RNA helicase DEAD3) (mDEAD3) (Embryonic RNA helicase) (D1PAS1 related sequence 2); DEAD/H (Asp-Glu-Ala-Asp/His) box polypeptide 3, X-linked; Dead3; Embryonic RNA helicase; Erh; fibroblast growth factor inducible 14; Fin14; mDEAD3; OTTMUSP00000018557
Gene Symbols: Ddx3x
Molecular weight: 73,101 Da
Basal Isoelectric point: 6.73  Predict pI for various phosphorylation states
Protein-Specific Antibodies or siRNAs from Cell Signaling Technology® Total Proteins
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DDX3

Protein Structure Not Found.


Cross-references to other databases:  STRING  |  BioGPS  |  Pfam  |  ENZYME  |  Phospho.ELM  |  NetworKIN  |  UniProtKB  |  Entrez-Gene  |  GenPept  |  Ensembl Gene  |  Ensembl Protein