Grik5 Protein Glutamate Receptor Kainate Type Subunit is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
GRIK5 (Glutamate Receptor Kainate Type Subunit 5), also known as KA2 (Kainate Receptor 2), is an ionotropic glutamate receptor subunit that forms functional kainate receptors when combined with other GRIK subunits. Kainate receptors play important roles in excitatory neurotransmission, synaptic plasticity, and neuronal development.
| Attribute |
Value |
| Protein Name |
Glutamate receptor kainate 5 |
| Gene |
GRIK5 |
| UniProt ID |
Q9NSU7 |
| Molecular Weight |
~106 kDa |
| Subcellular Localization |
Postsynaptic plasma membrane |
| Protein Family |
Ionotropic glutamate receptor (kainate) |
| Protein Structure |
Modular: ligand-binding domain (LBD), transmembrane domain (TMD), intracellular C-terminal domain |
GRIK5 is composed of:
- N-terminal domain (ATD): Affects receptor assembly and trafficking
- Ligand-binding domain (LBD): Binds glutamate and kainate agonists
- Transmembrane domain (TMD): Three membrane-spanning helices + pore loop
- C-terminal domain (CTD): Postsynaptic density interactions, phosphorylation sites
GRIK5 typically forms heteromeric receptors with GRIK2 or GRIK3 subunits, as it cannot form functional homomeric channels on its own.
- Mediates slow depolarizing responses to glutamate
- Contributes to synaptic integration in hippocampal and cortical neurons
- Modulates neuronal excitability
- Involved in both LTP and LTD at certain synapses
- Regulates presynaptic release probability
- Contributes to activity-dependent synaptic remodeling
- Regulates neurite outgrowth andaxon guidance
- Influences synapse formation during development
- Critical period plasticity in visual cortex
- Hippocampal CA3 pyramidal neurons: mossy fiber signaling
- Cerebellar granule cells: parallel fiber inputs
- Cortical interneurons: disinhibition mechanisms
- Kainate receptor signaling altered in AD brains
- May contribute to excitotoxicity in early stages
- GRIK5 expression changes in hippocampus
- Potential therapeutic target
- Altered glutamatergic signaling in basal ganglia
- Kainate receptors on dopaminergic neurons
- Contributes to motor circuit dysfunction
- Kainate receptors involved in seizure genesis
- GRIK5 mutations associated with epileptic encephalopathy
- Kainic acid model of temporal lobe epilepsy
- Altered kainate receptor expression in prefrontal cortex
- May affect NMDA receptor function indirectly
- GABAergic interneuron dysfunction
- Excitotoxicity mechanisms involve kainate receptors
- Motor neuron vulnerability
- Potential therapeutic intervention point
| Approach |
Status |
Notes |
| Antagonists |
Research |
LY382884, LY466365 in trials |
| Positive Allosteric Modulators |
Research |
Enhance receptor function |
| Gene Therapy |
Preclinical |
AAV delivery of modified receptors |
- Subtype selectivity (GRIK1-5, GRIK1-2 have distinct roles)
- Blood-brain barrier penetration
- Therapeutic window for excitability modulation
- Structure of kainate receptors - Science (2012) - PMID:22701012
- GRIK5 in hippocampal plasticity - J Neurosci (2009) - PMID:19176834
- Kainate receptors in epilepsy - Brain (2014) - PMID:24578528
- Therapeutic potential of kainate receptor modulators - Nat Rev Drug Discov (2016) - PMID:27007924
The study of Grik5 Protein Glutamate Receptor Kainate Type Subunit has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.