GNA15 is a protein encoded by the [GNA15](/genes/gna15) gene that functions as a G protein alpha subunit primarily expressed in hematopoietic cells. It activates phospholipase C beta, leading to calcium signaling. While mainly studied in immune cells, GNA15-mediated signaling has emerging roles in neuroinflammation and neurodegenerative diseases. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.
Gene: [GNA15](/genes/gna15)
UniProt: [P30679](https://www.uniprot.org/uniprot/P30679)
PDB: 1AZT
Molecular Weight: 41.3 kDa
Subcellular Localization: Plasma membrane
Protein Family: G alpha q/11 family
Structure
The GNA15 protein is a G protein alpha subunit characterized by canonical G protein domain architecture[@oldham2008]. Key structural features include:
GNA15 is a protein encoded by the [GNA15](/genes/gna15) gene that functions as a G protein alpha subunit primarily expressed in hematopoietic cells. It activates phospholipase C beta, leading to calcium signaling. While mainly studied in immune cells, GNA15-mediated signaling has emerging roles in neuroinflammation and neurodegenerative diseases. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.
Gene: [GNA15](/genes/gna15)
UniProt: [P30679](https://www.uniprot.org/uniprot/P30679)
PDB: 1AZT
Molecular Weight: 41.3 kDa
Subcellular Localization: Plasma membrane
Protein Family: G alpha q/11 family
Structure
The GNA15 protein is a G protein alpha subunit characterized by canonical G protein domain architecture[@oldham2008]. Key structural features include:
GTP-binding domain: Responsible for nucleotide binding and hydrolysis
Switch regions (I, II, III): Undergo conformational changes upon GTP binding and hydrolysis
Alpha-helical domain: Involved in effector interaction
N-terminal helix: Required for membrane association and receptor coupling
The protein adopts a similar fold to other Gα subunits, with six β-strands and five α-helices forming the core GTPase domain[@wall1995].
Normal Function
GNA15 is a G protein alpha subunit primarily expressed in hematopoietic cells, including [microglia](/cell-types/microglia), the resident immune cells of the brain[@hanisch2007]. Its normal functions include:
Phospholipase C activation: GNA15 activates phospholipase C beta (PLCβ), leading to the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol trisphosphate (IP3) and diacylglycerol (DAG)
Calcium signaling: IP3 production triggers calcium release from intracellular stores
Protein kinase C activation: DAG activates protein kinase C (PKC)
Microglial activation: GNA15-mediated signaling regulates microglial phagocytosis and cytokine release
Role in Neurodegeneration
GNA15 plays emerging roles in neurodegenerative diseases through its functions in [microglial activation](/mechanisms/microglial-activation) and [neuroinflammation](/mechanisms/neuroinflammation):
Alzheimer's Disease
GNA15-mediated microglial signaling contributes to chronic neuroinflammation in AD
Elevated GNA15 expression has been observed in AD brain tissue
Modulation of GNA15 signaling may reduce pro-inflammatory cytokine release
Parkinson's Disease
GNA15 is involved in microglial responses to α-synuclein aggregation
Genetic variants in GNA15 may influence PD susceptibility
[Oldham WM, Hamm HE, Heterotrimeric G protein activation by G-protein-coupled receptors (2008)](https://pubmed.ncbi.nlm.nih.gov/18043707/)
[Wall MA, Coleman DE, Lee E, et al, The structure of the G protein heterotrimer Gi alpha 1 beta 1 gamma 2 (1995)](https://pubmed.ncbi.nlm.nih.gov/8521505/)
[Hanisch UK, Kettenmann H, Microglia: active sensor and versatile effector cells in the normal and pathologic brain (2007)](https://pubmed.ncbi.nlm.nih.gov/17965643/)
[Syrovatkina V, Alegre KO, Dey R, Huang XY, Regulation, Functions, and Disease Mechanisms of G Protein-Coupled Receptor Kinases (2020)](https://pubmed.ncbi.nlm.nih.gov/31894570/)