Inositol 1,4,5-trisphosphate receptors in endocrine cells: Localization and association in hetero- and homotetramers

Frederick Nucifora, Alan H. Sharp, Sharon L. Milgram, Christopher A Ross

Research output: Contribution to journalArticle

Abstract

The inositol 1,4,5-trisphosphate receptor (IP3R) is an intracellular calcium channel involved in coupling cell membrane receptors to calcium signal transduction pathways within cells including endocrine cells. Several isoforms (I, II, and III) of IP3Rs have been identified, which are encoded by separate genes, and are expressed in many tissues with differing patterns of cellular expression. We have generated specific affinity-purified polyclonal anti-peptide antibodies to each of the three isoforms. Western blot analysis of RINm5F and ATt20 cells shows high levels of endogenously expressed type I and type III IP3R, but undetectable levels of type II. Immunofluorescence studies revealed an endoplasmic reticulum-like pattern similar to BiP, an ER marker. In contrast with previous claims, both type I and type III IP3Rs were absent from the secretory granules of ATt20 cells. Western blots of sucrose gradients and gel filtration probed with antibodies to either type I or type III showed a molecular weight of greater than 1,000 kDa consistent with a tetrameric structure. Co-immunoprecipitation experiments indicated that most of the receptors were present as heterotetramers. Homotetramers were identified for the type III IP3R; however, type I homotetramers were undetectable. These data suggest that molecular association of IP3Rs into heterotetrameric forms can contribute to the complexity of the regulation of Ca2+ release from ER by IP3Rs within cells.

Original languageEnglish (US)
Pages (from-to)949-960
Number of pages12
JournalMolecular Biology of the Cell
Volume7
Issue number6
StatePublished - Jun 1996

Fingerprint

Inositol 1,4,5-Trisphosphate Receptors
Endocrine Cells
Protein Isoforms
Western Blotting
Calcium-Sensing Receptors
Secretory Vesicles
Calcium Channels
Immunoprecipitation
Endoplasmic Reticulum
Gel Chromatography
Fluorescent Antibody Technique
Sucrose
Anti-Idiotypic Antibodies
Signal Transduction
Molecular Weight
Cell Membrane
Peptides
Antibodies
Genes

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cell Biology

Cite this

Inositol 1,4,5-trisphosphate receptors in endocrine cells : Localization and association in hetero- and homotetramers. / Nucifora, Frederick; Sharp, Alan H.; Milgram, Sharon L.; Ross, Christopher A.

In: Molecular Biology of the Cell, Vol. 7, No. 6, 06.1996, p. 949-960.

Research output: Contribution to journalArticle

@article{3f65aa2c53224bde9c5edac04044a815,
title = "Inositol 1,4,5-trisphosphate receptors in endocrine cells: Localization and association in hetero- and homotetramers",
abstract = "The inositol 1,4,5-trisphosphate receptor (IP3R) is an intracellular calcium channel involved in coupling cell membrane receptors to calcium signal transduction pathways within cells including endocrine cells. Several isoforms (I, II, and III) of IP3Rs have been identified, which are encoded by separate genes, and are expressed in many tissues with differing patterns of cellular expression. We have generated specific affinity-purified polyclonal anti-peptide antibodies to each of the three isoforms. Western blot analysis of RINm5F and ATt20 cells shows high levels of endogenously expressed type I and type III IP3R, but undetectable levels of type II. Immunofluorescence studies revealed an endoplasmic reticulum-like pattern similar to BiP, an ER marker. In contrast with previous claims, both type I and type III IP3Rs were absent from the secretory granules of ATt20 cells. Western blots of sucrose gradients and gel filtration probed with antibodies to either type I or type III showed a molecular weight of greater than 1,000 kDa consistent with a tetrameric structure. Co-immunoprecipitation experiments indicated that most of the receptors were present as heterotetramers. Homotetramers were identified for the type III IP3R; however, type I homotetramers were undetectable. These data suggest that molecular association of IP3Rs into heterotetrameric forms can contribute to the complexity of the regulation of Ca2+ release from ER by IP3Rs within cells.",
author = "Frederick Nucifora and Sharp, {Alan H.} and Milgram, {Sharon L.} and Ross, {Christopher A}",
year = "1996",
month = "6",
language = "English (US)",
volume = "7",
pages = "949--960",
journal = "Molecular Biology of the Cell",
issn = "1059-1524",
publisher = "American Society for Cell Biology",
number = "6",

}

TY - JOUR

T1 - Inositol 1,4,5-trisphosphate receptors in endocrine cells

T2 - Localization and association in hetero- and homotetramers

AU - Nucifora, Frederick

AU - Sharp, Alan H.

AU - Milgram, Sharon L.

AU - Ross, Christopher A

PY - 1996/6

Y1 - 1996/6

N2 - The inositol 1,4,5-trisphosphate receptor (IP3R) is an intracellular calcium channel involved in coupling cell membrane receptors to calcium signal transduction pathways within cells including endocrine cells. Several isoforms (I, II, and III) of IP3Rs have been identified, which are encoded by separate genes, and are expressed in many tissues with differing patterns of cellular expression. We have generated specific affinity-purified polyclonal anti-peptide antibodies to each of the three isoforms. Western blot analysis of RINm5F and ATt20 cells shows high levels of endogenously expressed type I and type III IP3R, but undetectable levels of type II. Immunofluorescence studies revealed an endoplasmic reticulum-like pattern similar to BiP, an ER marker. In contrast with previous claims, both type I and type III IP3Rs were absent from the secretory granules of ATt20 cells. Western blots of sucrose gradients and gel filtration probed with antibodies to either type I or type III showed a molecular weight of greater than 1,000 kDa consistent with a tetrameric structure. Co-immunoprecipitation experiments indicated that most of the receptors were present as heterotetramers. Homotetramers were identified for the type III IP3R; however, type I homotetramers were undetectable. These data suggest that molecular association of IP3Rs into heterotetrameric forms can contribute to the complexity of the regulation of Ca2+ release from ER by IP3Rs within cells.

AB - The inositol 1,4,5-trisphosphate receptor (IP3R) is an intracellular calcium channel involved in coupling cell membrane receptors to calcium signal transduction pathways within cells including endocrine cells. Several isoforms (I, II, and III) of IP3Rs have been identified, which are encoded by separate genes, and are expressed in many tissues with differing patterns of cellular expression. We have generated specific affinity-purified polyclonal anti-peptide antibodies to each of the three isoforms. Western blot analysis of RINm5F and ATt20 cells shows high levels of endogenously expressed type I and type III IP3R, but undetectable levels of type II. Immunofluorescence studies revealed an endoplasmic reticulum-like pattern similar to BiP, an ER marker. In contrast with previous claims, both type I and type III IP3Rs were absent from the secretory granules of ATt20 cells. Western blots of sucrose gradients and gel filtration probed with antibodies to either type I or type III showed a molecular weight of greater than 1,000 kDa consistent with a tetrameric structure. Co-immunoprecipitation experiments indicated that most of the receptors were present as heterotetramers. Homotetramers were identified for the type III IP3R; however, type I homotetramers were undetectable. These data suggest that molecular association of IP3Rs into heterotetrameric forms can contribute to the complexity of the regulation of Ca2+ release from ER by IP3Rs within cells.

UR - http://www.scopus.com/inward/record.url?scp=0029982351&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029982351&partnerID=8YFLogxK

M3 - Article

C2 - 8817000

AN - SCOPUS:0029982351

VL - 7

SP - 949

EP - 960

JO - Molecular Biology of the Cell

JF - Molecular Biology of the Cell

SN - 1059-1524

IS - 6

ER -