HOMER1

Description

The HOMER1 (homer scaffold protein 1) is a protein-coding gene located on chromosome 5.

Homer1, also known as Homer protein homolog 1 or Vesl and PSD-Zip45, is a neuronal protein encoded by the HOMER1 gene. It has two major splice variants, short-form (Homer1a) and long-form (Homer1b and c). Homer1a contains only the EVH1 domain, which is involved in protein interaction, while Homer1b and 1c possess both the EVH1 and coiled-coil domains. The coiled-coil domain further separates into N-terminal and C-terminal halves. The N-terminal half is predicted to be a parallel dimer, while the C-terminus half is a hybrid of dimeric and anti-parallel tetrameric coiled-coil. The long Homer is predicted to have a dumbbell-like structure with two pairs of EVH1 domains located on two sides of the long coiled-coil domain. Besides Homer1, mammals also have Homer2 and Homer3, which share a similar domain structure and alternatively spliced forms.

Homer1 is a scaffolding protein that plays a crucial role in postsynaptic signaling and synaptic plasticity. It acts as a bridge between various proteins, including the metabotropic glutamate receptors (GRM1 and GRM5), the inositol triphosphate receptor 1 (ITPR1), the dynamin 3 (DNM3), the ryanodine receptors (RYR1 and RYR2), and the scaffolding proteins SHANK1 and SHANK3. This bridging function facilitates the coupling of surface receptors to intracellular calcium release, ensuring the proper signal transduction across synapses. Homer1 also interacts with AGAP2, potentially linking GRM1 to the PI3 kinase pathway. The different isoforms of Homer1 exhibit distinct functions. Isoform 1 regulates the trafficking and surface expression of GRM5, while isoform 3 acts as a dominant negative regulator of synaptic metabotropic glutamate function, competing with isoform 1. Isoform 3 is implicated in the structural changes that occur during synaptic plasticity and neuronal development. Homer1 forms a complex with SHANK1, contributing to the structural and functional integrity of dendritic spines. Moreover, Homer1 negatively regulates T cell activation by inhibiting the calcineurin-NFAT pathway. It competes with calcineurin/PPP3CA for NFAT protein binding, preventing NFAT activation by PPP3CA.

HOMER1 is also known as HOMER, HOMER1A, HOMER1B, HOMER1C, SYN47, Ves-1.

Associated Diseases

WES Whole Exome Sequencing

Clinical Exome Sequencing