GRK7: G Protein-Coupled Receptor Kinase 7
Key regulator of cone opsin phototransduction deactivation in the retina
Gene Information Card
| Symbol | GRK7 |
|---|---|
| Full Name | G protein-coupled receptor kinase 7 |
| Gene Type | protein-coding |
| Chromosomal Location | 3q22.1 |
| NCBI Gene ID | 131890 ncbi.nlm.nih.gov/gene/131890 |
| Ensembl ID | ENSG00000147202 |
| UniProt ID | Q8WTQ7 |
| OMIM ID | 606987 |
| HGNC ID | 4562 |
| Aliases | GPRK7, RK7 |
Description
GRK7 encodes a member of the G protein-coupled receptor kinase (GRK) family that specifically phosphorylates light-activated cone opsins, initiating their deactivation and termination of the phototransduction cascade. It is expressed predominantly in cone photoreceptors of the retina and is essential for normal cone function and visual adaptation.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Cone dystrophy 4 (COD4) | Loss-of-function mutations in GRK7 impair cone opsin phosphorylation, leading to delayed photoresponse recovery and progressive cone degeneration. | OMIM #613093; ClinVar pathogenic variants |
| Retinitis pigmentosa (rare association) | Biallelic GRK7 variants may contribute to rod-cone dystrophy phenotypes in some families. | ClinVar; case reports |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Retina | 78.5 | High |
| Brain (cerebellum) | 1.2 | Low |
| Testis | 0.8 | Low |
| Heart | 0.3 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| ARPE-19 (retinal pigment epithelium) | 0.1 | Very low expression |
| Y79 (retinoblastoma) | 0.0 | Not expressed |
| HEK293 | 0.0 | Not expressed |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.416C>T (p.Pro139Leu) | Missense | Rare | Loss of kinase activity; associated with COD4 |
| c.988C>T (p.Arg330*) | Nonsense | Rare | Premature truncation; loss of function |
| c.1192G>A (p.Glu398Lys) | Missense | Rare | Impaired substrate binding; pathogenic |
Mutation functional classification
Loss of Function (LOF)
Most reported GRK7 mutations are loss-of-function, reducing or abolishing cone opsin phosphorylation and leading to cone dystrophy.
Gain of Function (GOF)
No gain-of-function mutations have been described in GRK7.
Dominant Negative (DN)
Heterozygous missense variants may exert dominant-negative effects by interfering with wild-type GRK7 dimerization or substrate access.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Phototransduction cascade (KEGG hsa04744)
• G protein-coupled receptor signaling pathway (Reactome R-HSA-372790)
Protein Summary
GRK7 is a 553-amino acid serine/threonine kinase that specifically phosphorylates light-activated cone opsins. It contains an N-terminal RGS homology domain, a central catalytic kinase domain, and a C-terminal membrane-targeting region. GRK7 localizes to cone outer segments and is critical for rapid deactivation of phototransduction, enabling high temporal resolution of cone-mediated vision.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GRK7 Knockout HEK293 Cell Line | EDJ-KQ9277 | Human | 131890 | Details Get a Quote |
| GRK7 Knockout HeLa Cell Line | EDJ-KQ58304 | Human | 131890 | Details Get a Quote |
| GRK7 Knockout A-549 Cell Line | EDJ-KQ66792 | Human | 131890 | Details Get a Quote |
| GRK7 Knockout HCT 116 Cell Line | EDJ-KQ75195 | Human | 131890 | Details Get a Quote |
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