PHKG2
Phosphorylase Kinase Catalytic Subunit Gamma 2
Gene Information Card
| Symbol | PHKG2 |
|---|---|
| Full Name | Phosphorylase Kinase Catalytic Subunit Gamma 2 |
| Gene Type | protein-coding |
| Chromosomal Location | 16p11.2 |
| NCBI Gene ID | 5261 ncbi.nlm.nih.gov/gene/5261 |
| Ensembl ID | ENSG00000156873 |
| UniProt ID | P15735 |
| OMIM ID | 172475 |
| HGNC ID | 8928 |
| Aliases | PHK-gamma 2, PHKgamma2, GSD IXC |
Description
PHKG2 (Phosphorylase Kinase Catalytic Subunit Gamma 2) is a protein-coding gene that encodes the gamma 2 catalytic subunit of phosphorylase kinase (PhK). PhK is a key regulatory enzyme in glycogen metabolism, activating glycogen phosphorylase to break down glycogen into glucose-1-phosphate. The gamma subunit contains the catalytic domain, and the gamma 2 isoform is predominantly expressed in liver and testis. Mutations in PHKG2 cause glycogen storage disease type IXC (GSD IXC), an autosomal recessive disorder characterized by liver glycogen accumulation, hepatomegaly, fasting hypoglycemia, and growth retardation.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Glycogen Storage Disease IXC (GSD IXC) | Loss-of-function mutations in PHKG2 impair phosphorylase kinase activity, preventing glycogen breakdown in the liver, leading to glycogen accumulation and hepatomegaly. | ClinVar, OMIM |
| Glycogen Storage Disease IX (general) | Deficiency of phosphorylase kinase activity due to PHKG2 mutations results in liver glycogenosis with variable severity. | OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.5 | High |
| Testis | 8.3 | Medium |
| Kidney | 3.1 | Low |
| Heart | 2.0 | Low |
| Skeletal Muscle | 1.5 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 15.2 | Liver cancer cell line, high expression |
| HEK293 | 4.8 | Embryonic kidney, moderate expression |
| K562 | 1.2 | Leukemia, low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.436C>T (p.Arg146Trp) | Missense | Rare | Loss of catalytic activity; associated with GSD IXC |
| c.838G>A (p.Gly280Arg) | Missense | Rare | Impaired enzyme function; reported in GSD IXC |
| c.100delG (p.Ala34Profs*24) | Frameshift | Rare | Premature truncation; loss of function |
Mutation functional classification
Loss of Function (LOF)
Most PHKG2 mutations are loss-of-function, reducing or abolishing phosphorylase kinase catalytic activity, leading to glycogen storage disease IXC.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported; inheritance is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • ATP binding | • protein kinase activity |
| • phosphorylase kinase activity | • glycogen metabolic process |
| • carbohydrate metabolic process | • signal transduction |
Pathways
• Glycogen breakdown (phosphorylase kinase activation)
• Glycogen metabolism
• cAMP signaling pathway
Protein Summary
The PHKG2 protein (UniProt P15735) is a 406-amino acid catalytic subunit of phosphorylase kinase. It contains a serine/threonine kinase domain that phosphorylates and activates glycogen phosphorylase. The gamma 2 isoform is liver-specific and essential for maintaining blood glucose levels during fasting. Defects in this protein disrupt glycogenolysis, causing glycogen storage disease type IXC.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| PHKG2 Knockout HEK293 Cell Line | EDJ-KQ1635 | Human | 5261 | Details Get a Quote |
| PHKG2 Knockout HeLa Cell Line | EDJ-KQ20004 | Human | 5261 | Details Get a Quote |
| PHKG2 Knockout A-549 Cell Line | EDJ-KQ21349 | Human | 5261 | Details Get a Quote |
| PHKG2 Knockout HCT 116 Cell Line | EDJ-KQ21350 | Human | 5261 | Details Get a Quote |
| PHKG2 Knockout HAP1 Cell Line | EDC07787 | Human | 5261 | Details Get a Quote |
