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inositol triphosphate [IP3] receptor P400 (ITPR, IP3-R)
Three distinct genes encode 3 similar IP3-receptors, with 69% sequence homology.
Function:
- intracellular channel that mediates Ca+2 release from the endoplasmic reticulum following stimulation by inositol 1,4,5-trisphosphate
- suggested to have protein kinase activity, but functional significance of this suggestion is unknown
- binds to homer via PPXXF motif in proline-rich region in the N-terminal cytoplasmic domain.
Structure: homologous to ryanodine receptor
Alternative splicing:
- different forms also produced by alternative splicing
Expression:
- present in all tissues tested
- highest levels in cortex & cerebellum
Interactions
molecular events
Related
inositol-1,4,5-triphosphate (IP3)
Specific
inositol 1,4,5-trisphosphate receptor type 1; IP3 receptor-1; type 1 inositol 1,4,5-trisphosphate receptor; type 1 insP3 receptor; IP3 receptor isoform 1; insP3R1; IP3R (ITPR1 INSP3R1)
inositol 1,4,5-trisphosphate receptor type 2; IP3 receptor-2; type 2 inositol 1,4,5-trisphosphate receptor; type 2 insP3 receptor; IP3 receptor isoform 2; insP3R2 (ITPR2)
inositol 1,4,5-trisphosphate receptor type 3; IP3 receptor-3; type 3 inositol 1,4,5-trisphosphate receptor; type 3 insP3 receptor; IP3 receptor isoform 3; insP3R3 (ITPR3)
General
Ca+2 channel
glycoprotein
ionotropic receptor
oligomerizing protein
phosphoprotein
transmembrane 8 protein
Properties
CONFIGURATION: tetramer
SIZE: MW = 1252 kD
COMPARTMENT: smooth endoplasmic reticulum
CELL: most cell types*
ORGANISM: eukaryote*
MOTIF: ligand-binding site
FOR-BINDING-OF: inositol-1,4,5-triphosphate
proline-rich region
MOTIF: proline residue (SEVERAL)
PPXXF motif
NAME: PPXXF motif
Ser phosphorylation site {CYS1}
ATP-binding site
NAME: ATP-binding site
SITE: UPF0405 protein TMEM103
Ser phosphorylation site {CYS2}
ATP-binding site
NAME: ATP-binding site
SITE: ATP2
ATP-binding site
NAME: ATP-binding site
SITE: ATP3
Ca+2-binding site
SITE: cytoplasm
Mg+2-binding site
transmembrane domain (8)
Ca+2-binding site
SITE: phenobarbital
ION-PERMEABILITY: Ca+2
MISC-INFO: INHIBITOR = ATP
CONDUCTANCE 20-80 PS
References
- Ferris et al Proc Natl Acad Sci U S A 1990
Mar;87(6):2147-51
- Mignery GA, Sdhof TC.
The ligand binding site and transduction mechanism in the
inositol-1,4,5-triphosphate receptor.
EMBO J. 1990 Dec;9(12):3893-8.
PMID: 2174351
- Yamamoto H, Maeda N, Niinobe M, Miyamoto E, Mikoshiba K.
Phosphorylation of P400 protein by cyclic AMP-dependent
protein kinase and Ca2+/calmodulin-dependent protein kinase II.
J Neurochem. 1989 Sep;53(3):917-23.
PMID: 2547906
- Miyawaki A, Furuichi T, Maeda N, Mikoshiba K.
Expressed cerebellar-type inositol 1,4,5-trisphosphate
receptor, P400, has calcium release activity in a fibroblast
L cell line.
Neuron. 1990 Jul;5(1):11-8.
PMID: 2164403-8
- Taylor CW, Marshall IC.
Calcium and inositol 1,4,5-trisphosphate receptors: a complex
relationship.
Trends Biochem Sci. 1992 Oct;17(10):403-7. Review.
Erratum in: Trends Biochem Sci 1992 Dec;17(12):493.
PMID: 1333657
- Sheng M.
Molecular organization of the postsynaptic specialization.
Proc Natl Acad Sci U S A. 2001 Jun 19;98(13):7058-61. Review.
PMID: 11416187
Component-of
molecular complex