PHKB Gene - Phosphorylase Kinase Regulatory Subunit Beta
Comprehensive gene card for PHKB, including genomic context, expression, mutations, and associated diseases.
Gene Information Card
| Symbol | PHKB |
|---|---|
| Full Name | Phosphorylase Kinase Regulatory Subunit Beta |
| Gene Type | Protein coding |
| Chromosomal Location | 16q12.1 |
| NCBI Gene ID | 5257 ncbi.nlm.nih.gov/gene/5257 |
| Ensembl ID | ENSG00000102893 |
| UniProt ID | Q93100 |
| OMIM ID | 172490 |
| HGNC ID | 8920 |
| Aliases | PHK, PHKB, phosphorylase b kinase regulatory subunit beta |
Description
The PHKB gene encodes the beta regulatory subunit of phosphorylase kinase (PhK), a key enzyme in glycogen metabolism. PhK phosphorylates and activates glycogen phosphorylase, which catalyzes the rate-limiting step of glycogenolysis. Mutations in PHKB cause glycogen storage disease type IX (GSD IX), characterized by hepatomegaly, hypoglycemia, and growth retardation. The beta subunit is essential for the assembly and regulation of the PhK hexadecameric complex.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Glycogen storage disease type IX (GSD IX) | Loss-of-function mutations in PHKB impair PhK activity, leading to defective glycogen breakdown and accumulation in liver and muscle. | ClinVar, OMIM |
| Glycogen storage disease IXb (GSD IXb) | Specific PHKB mutations cause a liver-predominant form of GSD IX with autosomal recessive inheritance. | OMIM #261750 |
| Glycogen storage disease IXc (GSD IXc) | Rare PHKB variants may contribute to combined liver and muscle involvement. | ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.3 | Medium |
| Skeletal Muscle | 8.7 | Medium |
| Heart | 6.5 | Low |
| Brain | 4.2 | Low |
| Kidney | 5.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 10.1 | Hepatocyte cell line |
| HeLa | 7.8 | Cervical carcinoma |
| K562 | 6.3 | Leukemia cell line |
| A549 | 5.9 | Lung carcinoma |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.210C>T (p.Arg70Ter) | Nonsense | <0.01% | Loss of function; associated with GSD IXb |
| c.1015G>A (p.Gly339Arg) | Missense | <0.01% | Reduced PhK activity; reported in ClinVar |
| c.1342delC (p.Leu448TrpfsTer12) | Frameshift | <0.01% | Loss of function; pathogenic in GSD IX |
| c.1A>G (p.Met1Val) | Missense | <0.01% | Start codon loss; likely pathogenic |
Mutation functional classification
Loss of Function (LOF)
Most PHKB mutations are loss-of-function, leading to reduced or absent phosphorylase kinase activity, causing glycogen storage disease type IX.
Gain of Function (GOF)
No gain-of-function mutations reported for PHKB.
Dominant Negative (DN)
No dominant-negative mutations reported; inheritance is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Glycogen metabolism (Reactome: R-HSA-70221)
• Phosphorylase kinase activation (Reactome: R-HSA-163754)
Protein Summary
The PHKB protein is the beta regulatory subunit of phosphorylase kinase (PhK), a hexadecameric enzyme complex (α4β4γ4δ4) that activates glycogen phosphorylase. The beta subunit (UniProt Q93100) is 396 amino acids long and contains multiple phosphorylation sites that regulate PhK activity. It is expressed in liver and muscle, where it integrates calcium and cAMP signaling to control glycogenolysis. Defects in PHKB disrupt this regulation, leading to glycogen storage disease type IX.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| PHKB Knockout HEK293 Cell Line | EDJ-KQ1636 | Human | 5257 | Details Get a Quote |
| PHKB Knockout A-549 Cell Line | EDJ-KQ21352 | Human | 5257 | Details Get a Quote |
| PHKB Knockout HCT 116 Cell Line | EDJ-KQ21353 | Human | 5257 | Details Get a Quote |
| PHKB Knockout HeLa Cell Line | EDJ-KQ21354 | Human | 5257 | Details Get a Quote |
