Inositol trisphosphate receptor

inositol 1,4,5-trisphosphate receptor, type 1[1]

Crystal structure of the ligand binding suppressor domain of type 1 inositol 1,4,5-trisphosphate receptor
Identifiers
Symbol ITPR1
Entrez 3708
HUGO 6180
OMIM 147265
RefSeq NM_002222
UniProt Q14643
Other data
Locus Chr. 3 p26.1
inositol 1,4,5-trisphosphate receptor, type 2
Identifiers
Symbol ITPR2
Entrez 3709
HUGO structure of the ligand binding suppressor domain of type 1 inositol 1,4,5-trisphosphate receptor 6181 Crystal structure of the ligand binding suppressor domain of type 1 inositol 1,4,5-trisphosphate receptor 6181
OMIM 600144
RefSeq NM_002223
UniProt Q14571
Other data
Locus Chr. 12 p11.23
inositol 1,4,5-trisphosphate receptor, type 3
Identifiers
Symbol ITPR3
Entrez 3710
HUGO 6182
OMIM 147267
RefSeq NM_002224
UniProt Q14573
Other data
Locus Chr. 6 p21.31

Inositol trisphosphate receptor (InsP3R) is a membrane glycoprotein complex acting as a Ca2+ channel activated by inositol trisphosphate (InsP3). InsP3R is very diverse among organisms, and is necessary for the control of cellular and physiological processes including cell division, cell proliferation, apoptosis, fertilization, development, behavior, learning and memory.[2] Inositol triphosphate receptor represents a dominant second messenger leading to the release of Ca2+ from intracellular store sites. There is strong evidence suggesting that the InsP3R plays an important role in the conversion of external stimuli to intracellular Ca2+ signals characterized by complex patterns relative to both space and time. For example, Ca2+ waves and oscillations.[3] The InsP3 receptor was first purified from rat cerebellum by neuroscientists Surachai Supattapone and Solomon Snyder at Johns Hopkins University School of Medicine.[4]

Distribution

It has a broad tissue distribution but is especially abundant in the cerebellum. Most of the InsP3Rs are found in the cell integrated into the endoplasmic reticulum.

Structure

The asymmetric structure consists of an N-terminal beta-trefoil domain and a C-terminal alpha helical domain with a folding pattern similar to an armadillo repeat fold. The split formed by the two terminals contains multiple arginine and lysine residues that coordinate the three phosphoryl groups of InsP3.[2] The InsP3R complex is formed of four 313 kDa subunits. In amphibians, fish and mammals there are 3 paralogs and these can form homo- or hetero-oligomers. InsP3R-1 is the most widely expressed of these three and is found in all tissue types and all developmental stages of life. It is additionally the means for further InsP3 receptor diversity in that it has as many as four splice sites with as many as 9 different optional exons or exon variants. Combinations of these can be introduced into a given transcript in order to modulate its pharmacological activity.

See also

References

  1. ↑ Bosanac I, Yamazaki H, Matsu-Ura T, Michikawa T, Mikoshiba K, Ikura M (January 2005). "Crystal structure of the ligand binding suppressor domain of type 1 inositol 1,4,5-trisphosphate receptor". Mol. Cell. 17 (2): 193–203. doi:10.1016/j.molcel.2004.11.047. PMID 15664189.
  2. 1 2 Bosanac I, Alattia JR, Mal TK, et al. (December 2002). "Structure of the inositol 1,4,5-trisphosphate receptor binding core in complex with its ligand". Nature. 420 (6916): 696–700. doi:10.1038/nature01268. PMID 12442173.
  3. ↑ Yoshida Y, Imai S (June 1997). "Structure and function of inositol 1,4,5-trisphosphate receptor". Jpn. J. Pharmacol. 74 (2): 125–37. doi:10.1254/jjp.74.125. PMID 9243320.
  4. ↑ Supattapone S, et al. J Biol Chem. 1988 Jan 25;263(3):1530-4.
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