Huntingtin and Huntingtin-associated protein 1 influence neuronal calcium signaling mediated by inositol-(1,4,5) triphosphate receptor type 1

Tie-Shan Tang, Huiping Tu, Edmond Y W Chan, Anton Maximov, Zhengnan Wang, Cheryl L Wellington, Michael R Hayden, Ilya Bezprozvanny

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Huntington's disease (HD) is caused by polyglutamine expansion (exp) in huntingtin (Htt). The type 1 inositol (1,4,5)-triphosphate receptor (InsP3R1) is an intracellular calcium (Ca2+) release channel that plays an important role in neuronal function. In a yeast two-hybrid screen with the InsP3R1 carboxy terminus, we isolated Htt-associated protein-1A (HAP1A). We show that an InsP3R1-HAP1A-Htt ternary complex is formed in vitro and in vivo. In planar lipid bilayer reconstitution experiments, InsP3R1 activation by InsP3 is sensitized by Httexp, but not by normal Htt. Transfection of full-length Httexp or caspase-resistant Httexp, but not normal Htt, into medium spiny striatal neurons faciliates Ca2+ release in response to threshold concentrations of the selective mGluR1/5 agonist 3,5-DHPG. Our findings identify a novel molecular link between Htt and InsP3R1-mediated neuronal Ca2+ signaling and provide an explanation for the derangement of cytosolic Ca2+ signaling in HD patients and mouse models.

Original languageEnglish
Pages (from-to)227-239
Number of pages13
Issue number2
Publication statusPublished - 17 Jul 2003


  • action potentials
  • animals
  • blotting, western
  • calcium
  • calcium channels
  • calcium signaling
  • cells, cultured
  • cerebellum
  • cerebral cortex
  • disease models, animal
  • dose-response relationship, drug
  • drug interactions
  • Fura-2
  • green fluorescent proteins
  • humans
  • Huntington disease
  • inositol 1,4,5-trisphosphate
  • inositol 1,4,5-trisphosphate receptors
  • lipid bilayers
  • luminescent proteins
  • methoxyhydroxyphenylglycol
  • nerve tissue proteins
  • neurons
  • nuclear proteins
  • patch-clamp techniques
  • peptide fragments
  • plasmids
  • protein binding
  • receptors, cytoplasmic and nuclear
  • recombinant proteins
  • time factors
  • two-hybrid system techniques

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