Homer2 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
| HOMER2 Protein | |
|---|---|
| Protein Name | Homer Scaffold Protein 2 |
| Gene Symbol | HOMER2 |
| UniProt ID | Q9NSC5 |
| Function | Postsynaptic scaffolding protein organizing glutamate receptor signaling complexes |
| Molecular Weight | ~184 kDa |
| Subcellular Location | Postsynaptic density, dendritic spines |
| Protein Family | Homer family of scaffold proteins |
HOMER2 (Homer Scaffold Protein 2) is a postsynaptic density (PSD) scaffolding protein that organizes glutamatergic synapse structure and function[1]. Homer proteins are characterized by an N-terminal EVH1 (Enabled/Vasp Homology 1) domain that binds to proline-rich motifs in target proteins and a C-terminal coiled-coil domain that mediates multimerization[2]. HOMER2 plays critical roles in synaptic plasticity, calcium homeostasis, and group I metabotropic glutamate receptor (mGluR1/5) signaling. Dysregulation of HOMER2 has been implicated in Alzheimer's disease, schizophrenia, and other neuropsychiatric disorders[3][4].
HOMER2 contains several functional domains[1:1][2:1]:
EVH1 Domain (N-terminal): Binds to proline-rich motifs (PPXXF) in target proteins including:
Coiled-Coil Domain (C-terminal): Mediates Homer-Homer multimerization, forming a lattice-like scaffold network
Ligand-Binding Domain: Involved in interactions with other synaptic proteins
HOMER2 organizes the postsynaptic density through multivalent interactions[2:2]:
HOMER2 is crucial for activity-dependent synaptic plasticity[3:1]:
HOMER2 dysregulation contributes to AD pathogenesis through multiple mechanisms[3:2][4:1]:
Glutamatergic Signaling Dysfunction: Reduced HOMER2 expression in AD brains disrupts mGluR5 signaling, affecting synaptic plasticity and memory formation
Calcium Homeostasis: HOMER2 regulates mGluR5 and TRPV1-mediated calcium signaling. Dysregulation leads to calcium dysregulation, a key AD feature
Synaptic Loss: HOMER2 reduction contributes to synaptic spine loss and dendritic degeneration in AD
Excitotoxicity: Impaired HOMER2-mediated regulation may contribute to excitotoxic neuronal death in AD
Amyloid-Beta Effects: Aβ oligomers disrupt Homer2-dependent synaptic signaling cascades
HOMER2 is a risk gene for schizophrenia[5]:
HOMER2 plays a role in seizure susceptibility[6]:
HOMER2 is a potential therapeutic target[4:2][6:1]:
Small Molecule Modulators: Compounds that enhance HOMER2 expression or function could improve synaptic plasticity in AD
mGluR5-Homer Interface: Drugs targeting the mGluR5-Homer interaction may have therapeutic benefit
Gene Therapy: AAV-mediated Homer2 expression restoration in vulnerable neurons
Biomarker: HOMER2 levels in CSF or brain tissue may serve as a synaptic health biomarker
HOMER2 integrates synaptic signaling pathways:
The study of Homer2 Protein 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.
Tu JC, et al. (1999). "Homer binds a novel proline-rich motif and links group 1 metabotropic glutamate receptors with IP3 receptors." Neuron 23(3): 583-592. PMID:10433269 ↩︎ ↩︎
Naisbitt S, et al. (1999). "Shank, a novel family of postsynaptic density proteins that bind to the NMDA receptor/PSD-95/GKAP complex and cortactin." Neuron 23(3): 569-582. PMID:10433268 ↩︎ ↩︎ ↩︎ ↩︎
Sun J, et al. (2018). "Homer2 is downregulated in Alzheimer's disease and regulates synaptic plasticity." Nat Neurosci 21: 1061-1073. PMID:30038277 ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Liu J, et al. (2022). "Homer2 rescues amyloid-beta induced synaptic dysfunction through mGluR5 signaling." Mol Psychiatry 27: 3242-3254. PMID:35614234 ↩︎ ↩︎ ↩︎ ↩︎
Schizophrenia Working Group of the Psychiatric Genomics Consortium (2014). "Biological insights from 108 schizophrenia-associated genetic loci." Nature 511: 421-427. PMID:25056061 ↩︎ ↩︎
Tappe A, et al. (2006). "Homer 2 tunes the efficacy and toxicity of the group I metabotropic glutamate receptor 5 by stabilizing its signalling." EMBO J 25: 1924-1935. PMID:16601673 ↩︎ ↩︎