N-terminal leucine/isoleucine/valine-binding protein (LIVBP)-like domain of the delta2 receptor of an orphan glutamate receptor family
N-terminal leucine/isoleucine/valine-binding protein (LIVBP)-like domain of the delta2 receptor of an orphan glutamate receptor family. While this N-terminal domain belongs to the periplasmic-binding fold type I superfamily, the glutamate-binding domain of the iGluR is structurally homologous to the periplasmic-binding fold type II. The LIVBP-like domain of iGluRs is thought to play a role in the initial assembly of iGluR subunits, but it is not well understood how this domain is arranged and functions in intact iGluR. Although the delta receptors are a member of the ionotropic glutamate receptor family, they cannot be activated by AMPA, kainate, NMDA, glutamate, or any other ligands. Phylogenetic analysis shows that both GluRdelta1 and GluRalpha2 are closer related to non-NMDA receptors. GluRdelta2 was shown to function as an AMPA-like receptor by mutation analysis. Moreover, targeted disruption of GluRdelta2 gene caused motor coordination impairment, Purkinje cell maturation, and long-term depression of synaptic transmission. It has been suggested that GluRdelta2 is the receptor for cerebellin 1, a glycoprotein of the Clq and tumor necrosis factor family that is secreted from cerebellar granule cells.
Marchler-Bauer A et al. (2017), "CDD/SPARCLE: functional classification of proteins via subfamily domain architectures.",