Biology:DHX30
The ATP-dependent RNA helicase DHX30 is an enzyme that in humans is encoded by the DHX30 (DExH-Box Helicase 30) gene.
DHX30 is one of many RNA helicases in the DExH superfamily, which unwind double-stranded sections of RNA or RNA/DNA hybrids and restructure RNA/protein complexes.[1][2][3][4] Disease-causing (pathogenic) mutations in the DHX30 gene cause DHX30 syndrome, which can include symptoms such as global developmental delay, intellectual disability, severe speech impairment, gait abnormalities, low muscle tone, autistic features, and seizures.[1][5]
Function
There are 6 known superfamilies of RNA helicases. DHX30 belongs to superfamily 2, which is characterized by a DExH or DExD signature in the ATP-binding motif II, and contains >50 human gene members. These RNA helicases bind and hydrolyze ATP, and their main function is to bind and unwind nucleic acids.[2][5]
Expression of DHX30 is ubiquitous,[6] and found in the brain from early embryonic stages through at least 6 years of age.[2] Like other DExH helicases, DHX30 enzyme is a processive helicase, which unwinds double-stranded RNA as it moves.[1][3] The DHX30 gene has two promoters, and the alternatively spliced isoform contains a predicted mitochondrial targeting sequence.[7] DHX30 is localized to and active in both the cytosol and mitochondria[8][7] and thought to link mitochondrial function, ribosome biogenesis, and global translation.[7] DHX30 functions within stress granules, which are large protein/RNA complexes in the cytoplasm where mRNAs are sequestered during translation shutdown events resulting from cellular stresses.[2][1][7] DHX30 protein is also localized to mitochondrial RNA granules, with roles in RNA processing and mitochondrial ribosome biogenesis.[8] DHX30 is also a mitochondrial G-quadruplex binding protein, and can unfold mitochondrial DNA G-quadruplex structures.[9]
Structure
Starting from the N-terminus, the human DHX30 protein contains two double stranded RNA-binding domains (dsRBD1, residues 53–145, and dsRBD2, residues 245–338), a central helicase core consisting of an ATP-binding RecA-like domain (residues 444–612) and a helicase C-terminal RecA-like domain (residues 654–827) followed by winged-helix (WH), rachet-like (RL) and oligosaccharide binding (OB) domains.[2] The presence of C-terminal WH, RL, and OB domains are a distinguishing characteristic of DExH helicases that provide a binding tunnel for single stranded RNA as it is unwound from double stranded RNA.[2]
Clinical significance
DHX30 syndrome
Several different helicases are specifically needed for each gene’s precise expression and RNA metabolism. Neurons appear to have exacting requirements for proteins involved in RNA metabolism, as neurodevelopmental disorders are observed in individuals with pathogenic mutations in many of the genes involved in RNA metabolic processes, including 5 DEAH-box RNA helicases (DHX9, DHX30, DHX37, DHX16, and DHX34) and 7 DEAD-box RNA helicases (DDX3X, DDX6, EIF4A2, DDX23, DDX54, DDX59, and EIF4A3).[2][4]
DHX30, as with many DEAD/DEAH-box RNA helicases, are intolerant to missense mutation.[4][5] Heterozygous missense, frameshift, and nonsense DHX30 variants are seen in humans and cause the neurodevelopmental disorder DHX30 syndrome (OMIM*616423), formerly known as NEDMIAL (Neurodevelopmental Disorder characterized with severe Motor Impairment and Absent Language, OMIM* 617804), also known as DHX30-associated neurodevelopmental disorders.[1][2][5] DHX30’s RNA helicase activity is disrupted by missense variants in its helicase core motifs by impairing either its ATPase activity or RNA binding ability.[2][5] It appears that stress granules form aberrantly when DHX30 is mutated, reducing global translation.[1][5][7]
Individuals with DHX30 syndrome may have all or some of the following symptoms, with differing severity: global developmental delay, intellectual disability, severe speech impairment, ataxia, hypotonia, differences in brain structure, strabismus, autistic features, and seizures.[1][5]
Role in cancer
DHX30 has been shown to interact with pro-apoptotic transcripts in cancer cells, reducing the chance of apoptosis, which suggests a possible role as a future target in cancer therapeutic development.[7]
Interactions
- FASTKD2[8]
- FASTKD5[7]
- MRPL11[7]
- MPRS22[7]
- Ribosomal subunit 80s[10]
- Mitochondrial endonuclease G (EndoG)[11] (Xu et al., (2025)
See also
- DHX30 syndrome
- Eukaryotic translation
- DExD/H box proteins
- DDX3X
- Neurodevelopmental disorder
- DEAD box
- RNA helicase
- RNA helicase database
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 "De Novo Missense Mutations in DHX30 Impair Global Translation and Cause a Neurodevelopmental Disorder". American Journal of Human Genetics 101 (5): 716–724. November 2017. doi:10.1016/j.ajhg.2017.09.014. PMID 29100085.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 "The role of DEAD- and DExH-box RNA helicases in neurodevelopmental disorders". Frontiers in Molecular Neuroscience 17. 2024. doi:10.3389/fnmol.2024.1414949. PMID 39149612.
- ↑ 3.0 3.1 "The Story of RNA Unfolded: The Molecular Function of DEAD- and DExH-Box ATPases and Their Complex Relationship with Membraneless Organelles". Annual Review of Biochemistry 93 (1): 79–108. August 2024. doi:10.1146/annurev-biochem-052521-121259. PMID 38594920.
- ↑ 4.0 4.1 4.2 "DEAD/DEAH-box RNA helicases shape the risk of neurodevelopmental disorders". Trends in Genetics 41 (5): 437–449. May 2025. doi:10.1016/j.tig.2024.12.006. PMID 39828505.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 "Genotype-phenotype correlations and novel molecular insights into the DHX30-associated neurodevelopmental disorders". Genome Medicine 13 (1). May 2021. doi:10.1186/s13073-021-00900-3. PMID 34020708.
- ↑ "Tissue expression of DHX30 - Summary - The Human Protein Atlas". https://www.proteinatlas.org/ENSG00000132153-DHX30/tissue.
- ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 "DHX30 Coordinates Cytoplasmic Translation and Mitochondrial Function Contributing to Cancer Cell Survival". Cancers (Basel) 13 (17): 4412. August 2021. doi:10.3390/cancers13174412. PMID 34503222.
- ↑ 8.0 8.1 8.2 "Mitochondrial RNA Granules Are Centers for Posttranscriptional RNA Processing and Ribosome Biogenesis". Cell Reports 10 (6): 920–932. February 2015. doi:10.1016/j.celrep.2015.01.030. PMID 25683715.
- ↑ "A subcellular selective APEX2-based proximity labeling used for identifying mitochondrial G-quadruplex DNA binding proteins". Nucleic Acids Research 53 (1). January 2025. doi:10.1093/nar/gkae1259. PMID 39718986.
- ↑ "RAPIDASH: Tag-free enrichment of ribosome-associated proteins reveals composition dynamics in embryonic tissue, cancer cells, and macrophages". Molecular Cell 84 (18): 3545–3563.e25. September 2024. doi:10.1016/j.molcel.2024.08.023. PMID 39260367.
- ↑ "Endonuclease G promotes hepatic mitochondrial respiration by selectively increasing mitochondrial tRNAThr production". Proceedings of the National Academy of Sciences of the United States of America 122 (1). January 2025. doi:10.1073/pnas.2411298122. PMID 39752519. Bibcode: 2025PNAS..12211298X.
 |  |
