InnateDB: Systems Biology of the Innate Immune Response

Mus musculus Protein: Homer1

Summary

InnateDB Protein

IDBP-172666.6

Last Modified

2014-10-13 [Report errors or provide feedback]

Gene Symbol

Homer1

Protein Name

homer homolog 1 (Drosophila)

Synonyms

homer-1; PSD-Zip45; SYN47; Ves-1; vesl-1;

Species

Mus musculus

Ensembl Protein

ENSMUSP00000078093

InnateDB Gene

IDBG-172658 (Homer1)

Protein Structure

UniProt Annotation

Function

Postsynaptic density scaffolding protein. Binds and cross-links cytoplasmic regions of GRM1, GRM5, ITPR1, DNM3, RYR1, RYR2, SHANK1 and SHANK3. By physically linking GRM1 and GRM5 with ER-associated ITPR1 receptors, it aids the coupling of surface receptors to intracellular calcium release. May also couple GRM1 to PI3 kinase through its interaction with AGAP2. Isoform 1 regulates the trafficking and surface expression of GRM5. Differentially regulates the functions of the calcium activated channel ryanodine receptors RYR1 and RYR2. Isoform 1 decreases the activity of RYR2, and increases the activity of RYR1, whereas isoform 5 counteracts the effects by competing for binding sites. Isoform 3 regulates the trafficking and surface expression of GRM5. Isoform 5 acts as a natural dominant negative, in dynamic competition with constitutively expressed isoform 1, isoform 2 and isoform 3 to regulate synaptic metabotropic glutamate function. Isoform 5, may be involved in the structural changes that occur at synapses during long-lasting neuronal plasticity and development (By similarity). {ECO:0000250}.

Subcellular Localization

Cytoplasm {ECO:0000269PubMed:24153177}. Cell junction, synapse, postsynaptic cell membrane, postsynaptic density {ECO:0000269PubMed:24153177}. Cell junction, synapse {ECO:0000269PubMed:24153177}. Note=Isoform 1 inhibits surface expression of GRM5 causing it to be retained in the endoplasmic reticulum. The N-terminal of isoform 2 may facilitate trafficking of the complex with GRM5 from the endoplasmic reticulum (ER) to the plasma membrane (PM).

Disease Associations

Tissue Specificity

Isoform 1, isoform 3 and isoform 5 are expressed in skeletal muscle at the level of the Z line, in heart, forebrain and cerebellum. Isoform 2, is a minor isoform and is expressed in cardiac and skeletal muscle. Isoform 5 is expressed in the postsynaptic region of neurons. {ECO:0000269PubMed:12379179, ECO:0000269PubMed:24153177}.

Comments

Interactions

Number of Interactions

This gene and/or its encoded proteins are associated with 14 experimentally validated interaction(s) in this database.
They are also associated with 12 interaction(s) predicted by orthology.

Experimentally validated
Total	14 [view]
Protein-Protein	13 [view]
Protein-DNA	1 [view]
Protein-RNA	0
DNA-DNA	0
RNA-RNA	0
DNA-RNA	0

Predicted by orthology
Total	12 [view]

Gene Ontology

Molecular Function

Accession	GO Term
GO:0005102	receptor binding
GO:0005515	protein binding
GO:0031802	type 5 metabotropic glutamate receptor binding
GO:0032947	protein complex scaffold
GO:0035256	G-protein coupled glutamate receptor binding
GO:0042802	identical protein binding
GO:0044325	ion channel binding
GO:0046982	protein heterodimerization activity
GO:0097110	scaffold protein binding

Biological Process

GO:0003009	skeletal muscle contraction
GO:0007216	G-protein coupled glutamate receptor signaling pathway
GO:0007623	circadian rhythm
GO:0035094	response to nicotine
GO:0035418	protein localization to synapse
GO:0042220	response to cocaine
GO:0048148	behavioral response to cocaine
GO:0048741	skeletal muscle fiber development
GO:0048875	chemical homeostasis within a tissue
GO:0051592	response to calcium ion
GO:0051928	positive regulation of calcium ion transport
GO:0090279	regulation of calcium ion import
GO:2001256	regulation of store-operated calcium entry
GO:2001257	regulation of cation channel activity

Cellular Component

GO:0005737	cytoplasm
GO:0005886	plasma membrane
GO:0016020	membrane
GO:0030018	Z disc
GO:0030054	cell junction
GO:0030424	axon
GO:0030425	dendrite
GO:0043005	neuron projection
GO:0043025	neuronal cell body
GO:0043034	costamere
GO:0043198	dendritic shaft
GO:0045177	apical part of cell
GO:0045202	synapse
GO:0045211	postsynaptic membrane
GO:0060076	excitatory synapse
GO:0097481	neuronal postsynaptic density