ARHGEF9
Rho Guanine Nucleotide Exchange Factor 9
Gene Information Card
| Symbol | ARHGEF9 |
|---|---|
| Full Name | Rho Guanine Nucleotide Exchange Factor 9 |
| Gene Type | Protein coding |
| Chromosomal Location | Xq11.1 |
| NCBI Gene ID | 23229 ncbi.nlm.nih.gov/gene/23229 |
| Ensembl ID | ENSG00000131089 |
| UniProt ID | O43307 |
| OMIM ID | 300429 |
| HGNC ID | 14561 |
| Aliases | COLLYBISTIN, GEF9, HPEM-2, KIAA0424 |
Description
ARHGEF9 encodes collybistin, a brain-specific guanine nucleotide exchange factor (GEF) that activates the small GTPase CDC42. It is essential for the clustering of gephyrin and glycine/GABA-A receptors at inhibitory synapses. Mutations in ARHGEF9 cause X-linked intellectual disability with epilepsy and hyperekplexia.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| X-linked intellectual disability with epilepsy | Loss-of-function mutations impair CDC42 activation, disrupting inhibitory synapse formation | ClinVar, OMIM |
| Hyperekplexia | Defective collybistin reduces glycine receptor clustering at synapses | OMIM |
| Epileptic encephalopathy, early infantile | Missense variants disrupt GEF activity and synaptic localization | ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.5 | High |
| Cerebral cortex | 15.2 | High |
| Cerebellum | 10.8 | High |
| Testis | 3.1 | Low |
| Heart | 0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| SH-SY5Y | 8.4 | Neuronal model |
| HEK293 | 0.2 | Low expression |
| U-87 MG | 1.1 | Glial cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.139C>T (p.Arg47*) | Nonsense | <0.01% | Loss of function, truncation |
| c.497G>A (p.Arg166His) | Missense | <0.01% | Impaired GEF activity |
| c.1066C>T (p.Arg356Trp) | Missense | <0.01% | Reduced CDC42 binding |
Mutation functional classification
Loss of Function (LOF)
Nonsense and frameshift variants leading to truncated or absent collybistin protein, causing X-linked intellectual disability and epilepsy.
Gain of Function (GOF)
Not reported in ARHGEF9.
Dominant Negative (DN)
Missense variants (e.g., p.Arg166His) may interfere with wild-type collybistin function in heterozygous females.
View complete mutation data：
Gene Ontology (GO)
| • GTPase activator activity | • Rho guanyl-nucleotide exchange factor activity |
| • CDC42 binding | • synaptic membrane |
| • GABAergic synapse | • postsynaptic density |
Pathways
• CDC42 signaling
• GABAergic synapse
• Rho GTPase cycle
Protein Summary
Collybistin is a 516-amino acid protein containing a RhoGEF domain and a PH domain. It specifically activates CDC42 by exchanging GDP for GTP. It localizes to postsynaptic sites and is required for gephyrin-dependent clustering of inhibitory neurotransmitter receptors.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| ARHGEF9 Knockout HEK293 Cell Line | EDJ-KQ7899 | Human | 23229 | Details Get a Quote |
| ARHGEF9 Knockout A-549 Cell Line | EDJ-KQ33502 | Human | 23229 | Details Get a Quote |
| ARHGEF9 Knockout HCT 116 Cell Line | EDJ-KQ33503 | Human | 23229 | Details Get a Quote |
| ARHGEF9 Knockout HeLa Cell Line | EDJ-KQ33504 | Human | 23229 | Details Get a Quote |
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