SMG9
SMG9 Nonsense Mediated Decay Factor
Gene Information Card
| Symbol | SMG9 |
|---|---|
| Full Name | SMG9 nonsense mediated mRNA decay factor |
| Gene Type | protein-coding |
| Chromosomal Location | 19q13.32 |
| NCBI Gene ID | 56006 ncbi.nlm.nih.gov/gene/56006 |
| Ensembl ID | ENSG00000105672 |
| UniProt ID | Q9H0W8 |
| OMIM ID | 613176 |
| HGNC ID | 25763 |
| Aliases | FLJ10895, MGC138290, MGC138291 |
Description
SMG9 is a core component of the nonsense-mediated mRNA decay (NMD) complex, which degrades mRNAs containing premature termination codons to prevent the production of truncated, potentially harmful proteins. The protein interacts with SMG1, SMG8, and other NMD factors to regulate mRNA surveillance. Mutations in SMG9 cause an autosomal recessive disorder characterized by congenital heart defects, intellectual disability, microcephaly, and dysmorphic features.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| SMG9 deficiency syndrome (heart defects, intellectual disability, microcephaly) | Loss-of-function mutations impair NMD, leading to accumulation of aberrant transcripts and developmental defects | PMID: 27866747, 30333007 |
| Congenital heart disease | Disrupted NMD affects cardiac development gene expression | PMID: 27866747 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Heart | 12.5 | Medium |
| Brain | 9.8 | Medium |
| Testis | 15.2 | High |
| Liver | 6.3 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 14.1 | High expression |
| HeLa | 11.5 | Medium expression |
| K562 | 8.9 | Medium expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1096C>T (p.Arg366*) | Nonsense | Rare | Loss of function; truncates protein |
| c.1A>G (p.Met1?) | Start loss | Rare | Loss of function; no translation initiation |
| c.1042_1043del (p.Leu348Glufs*2) | Frameshift | Rare | Loss of function; premature stop |
Mutation functional classification
Loss of Function (LOF)
Most reported SMG9 mutations are loss-of-function (nonsense, frameshift, start loss), leading to NMD deficiency.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported; disease is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • nonsense-mediated mRNA decay (GO:0000184) | • mRNA catabolic process (GO:0006402) |
| • SMG1-8-9 complex (GO:1990531) | • cytoplasm (GO:0005737) |
| • protein binding (GO:0005515) |
Pathways
• Nonsense-Mediated Decay (NMD) - Reactome R-HSA-927802
• mRNA Surveillance Pathway - KEGG hsa03015
Protein Summary
SMG9 is a 48 kDa protein that forms a stable complex with SMG8 and SMG1, regulating the kinase activity of SMG1 in the NMD pathway. It contains an N-terminal domain that mediates interaction with SMG8 and a C-terminal region involved in SMG1 binding. The protein is ubiquitously expressed, with highest levels in testis and heart.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SMG9 Knockout HEK293 Cell Line | EDJ-KQ15367 | Human | 56006 | Details Get a Quote |
| SMG9 Knockout A-549 Cell Line | EDJ-KQ46110 | Human | 56006 | Details Get a Quote |
| SMG9 Knockout HCT 116 Cell Line | EDJ-KQ46111 | Human | 56006 | Details Get a Quote |
| SMG9 Knockout HeLa Cell Line | EDJ-KQ46112 | Human | 56006 | Details Get a Quote |
