The type 1 inositol (1,4,5)-trisphosphate receptor (InsP(3)R1) is an intracellular calcium (Ca(2+)) release channel that plays an important role in neuronal function. In yeast two-hybrid screen of rat brain cDNA library with the InsP(3)R1 carboxy-terminal bait we isolated multiple clones of neuronal cytoskeletal protein 4.1N. We mapped the 4.1N-interaction site to a short fragment (50 amino aci...

The inositol 1,4,5-trisphosphate receptor (InsP(3)R), an intracellular calcium channel, has three isoforms with >65% sequence homology, yet the isoforms differ in their function and regulation by post-translational modifications. We showed previously that InsP(3)R-1 is functionally modified by O-linked β-N-acetylglucosamine glycosylation (O-GlcNAcylation) (Rengifo, J., Gibson, C. J., Winkler, E...

In cerebellum, inositol trisphosphate- (InsP(3)-) gated Ca channels play a key role in learning, though they exhibit a low sensitivity to InsP(3) compared to peripheral tissues. In the present study, the cerebellar InsP(3) receptor is shown to be associated with a novel inhibitor of InsP(3) binding. (3)H-InsP(3) binding studies indicated that this inositol trisphosphate receptor inhibitor (IRI)...

Activation of InsP(3)Rs (InsP(3) receptors) represents the major mechanism underlying intracellular calcium release in non-excitable cells such as hepatocytes and exocrine cells from the pancreas and salivary glands. Modulation of calcium release through InsP(3)Rs is therefore a major route whereby the temporal and spatial characteristics of calcium waves and oscillations can potentially be 'sh...

The objective was to quantify the retention of digesta and evaluate the degradation of phytate or inositol hexakisphosphate (InsP(6)) and lower inositol phosphates (InsP₅, InsP₄, InsP₃, and InsP₂) in the stomach at different times after feeding pigs a fermented liquid diet with microbial phytase or a nonfermented diet with or without microbial phytase. Six barrows fitted with gastric cannulas w...

Inositol hexakisphosphate (InsP(6)) is a member of the inositol polyphosphate group that participates in numerous intracellular signaling pathways. Cheung and colleagues previously reported that InsP(6) stimulated double-strand break repair by nonhomologous end joining (NHEJ) in cell-free extracts and that InsP(6) binding by the Ku70/80 subunit of the DNA-dependent protein kinase (DNA-PK) was r...

27 The synaptic plasticity literature has focused on establishing necessity and sufficiency as 28 two essential and distinct features in causally relating a signaling molecule to plasticity 29 induction, an approach that has been surprisingly lacking in the intrinsic plasticity 30 literature. Here, we complemented the recently established necessity of inositol 31 trisphosphate (InsP 3) receptor...

Myo-inositol-1,2,3,4,5,6-hexakisphosphate (InsP(6)), also known as phytic acid, accumulates in large quantities in plant seeds, serving as a phosphorus reservoir, but is an animal antinutrient and an important source of water pollution. Here, we report that Gle1 (GLFG lethal 1) in conjunction with InsP(6) functions as an activator of the ATPase/RNA helicase LOS4 (low expression of osmotically r...

Inositol 1,4,5-trisphosphate receptors (InsP(3)Rs) were recently demonstrated to be activated independently of InsP(3) by a family of calmodulin (CaM)-like neuronal Ca(2+)-binding proteins (CaBPs). We investigated the interaction of both naturally occurring long and short CaBP1 isoforms with InsP(3)Rs, and their functional effects on InsP(3)R-evoked Ca(2+) signals. Using several experimental pa...

The precise localization and role of inositol 1,4,5-trisphosphate (InsP(3)) receptors (InsP(3)Rs) in cardiac muscle cells are largely unknown. It is believed that waves and oscillations in cytosolic free calcium triggered by activation of InsP(3)Rs underlie modifications of cellular responses that lead to changes in gene expression in other cells. However, how changes in cytosolic calcium alter...