Homer proteins and InsP3 receptors co-localise in the longitudinal sarcoplasmic reticulum of skeletal muscle fibres

Salanova, Michele; Priori, Giuseppina; Barone, Virginia; Intravaia, Elena; Flucher, Bernhard E.; Ciruela, Francisco; Ra, McIlhinney; Parys, Jan B.; Mikoshiba, Katsuhiko; Sorrentino, Vincenzo

doi:10.1016/s0143416002001549

Cited by 51 publications

(66 citation statements)

References 32 publications

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“…In resting A7r5 cells, IP3R1 is precisely concentrated in that region. In some cell types, it was shown that IP3R1 localization could be restricted by its interaction with scaffolding proteins such as homer (Tu et al, 1998;Salanova et al, 2002) or ankyrin-B (Mohler et al, 2002). A restricted localization by interaction with cytoskeletal proteins could also be responsible for IP3R1 localized at the cell periphery (Sugiyama et al, 2000).…”

Section: Potential Role Of Vesicle Trafficking In Ip3r1 Redistributionmentioning

confidence: 99%

Microtubule-dependent redistribution of the type-1 inositol 1,4,5-trisphosphate receptor in A7r5 smooth muscle cells

Vermassen

Acker

Annaert

et al. 2003

Journal of Cell Science

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IntroductionCellular activation by many agonists results in the stimulation of phospholipase C (PLC) and the subsequent hydrolysis of phosphatidylinositol 4,5-bisphosphate to inositol 1,4,5-trisphosphate (IP 3) and diacylglycerol (DAG) (Berridge, 1993). Each of these two molecules exerts a specific effect in the cell. The increased DAG concentration leads to the activation of protein kinase C (PKC) while IP3 binds to the IP3 receptor (IP3R), an intracellular Ca 2+ -release channel located in the endoplasmic reticulum (ER), thereby inducing Ca 2+ release from internal stores. A prolonged stimulation of cells with agonists, however, results in downregulation of the IP 3Rs and this appears to be a cell-and agonist-specific process (Sipma et al., 1998;Wojcikiewicz, 1995). This downregulation results from an accelerated IP3R degradation (Wojcikiewicz et al., 1994) and is mediated by the ubiquitin-proteasome pathway (Oberdorf et al., 1999). Ca 2+ signals evoked by agonist stimulation have complex temporal and spatial characteristics, and the underlying mechanisms are not yet fully understood (Berridge et al., 1998). The differential regulation of the IP3R isoforms by various modulators of IP 3-induced Ca 2+ release, such as IP3, cytosolic Ca 2+ , ATP, calmodulin and phosphorylation by several kinases,

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Section: Potential Role Of Vesicle Trafficking In Ip3r1 Redistributionmentioning

confidence: 99%

Microtubule-dependent redistribution of the type-1 inositol 1,4,5-trisphosphate receptor in A7r5 smooth muscle cells

Vermassen

Acker

Annaert

et al. 2003

Journal of Cell Science

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“…at ASPET Journals on May 10, 2018 jpet.aspetjournals.org ryanodine receptors-1 (RyR-1) (Salanova et al, 2002). In the same sections, K v 7.2-and K v 7.3-positive striations were thin and nonoverlapping with those recognized by anti-AnkG antibodies, being instead positioned between each pair of thick AnkG-labeled triads; these results suggest the possible expression of K v 7.2 and K v 7.3 subunits in a sarcomeric pattern at the level of the Z-line.…”

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confidence: 99%

“…A similar Z-line distribution to K v 7.2 has been also observed for K v 7.3, whereas K v 7.4 expression seems restricted to the plasma membrane. It is noteworthy that K v 7.2 and K v 7.3 subunits localize in intracellular regions where InsP 3 R and the scaffolding protein Homer have been identified (Salanova et al, 2002). Although the precise functional and structural inter-relationships between these Z-line and sarcoplasmic reticulum proteins is still debated (Volpe et al, 2004), it seems plausible that they may regulate the function of the sarcoplasmic reticulum, thereby controlling skeletal muscle Ca 2ϩ homeostasis and excitation-contraction coupling.…”

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confidence: 99%

Expression, Localization, and Pharmacological Role of K_v7 Potassium Channels in Skeletal Muscle Proliferation, Differentiation, and Survival after Myotoxic Insults

Iannotti

Panza²,

Barrese³

et al. 2009

J Pharmacol Exp Ther

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“…Homer proteins are expressed in skeletal muscle and localize to the Z-disk/costamere complex (26). Homer protein expression is highly regulated in skeletal muscle, as indicated by expression profiling studies using models of muscle regeneration and mechanical overload (4,28).…”

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confidence: 99%

Mice Lacking Homer 1 Exhibit a Skeletal Myopathy Characterized by Abnormal Transient Receptor Potential Channel Activity

Stiber

Zhang

Burch

et al. 2008

Molecular and Cellular Biology

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Transient receptor potential (TRP) channels are nonselective cation channels, several of which are expressed in striated muscle. Because the scaffolding protein Homer 1 has been implicated in TRP channel regulation, we hypothesized that Homer proteins play a significant role in skeletal muscle function. Mice lacking Homer 1 exhibited a myopathy characterized by decreased muscle fiber cross-sectional area and decreased skeletal muscle force generation. Homer 1 knockout myotubes displayed increased basal current density and spontaneous cation influx. This spontaneous cation influx in Homer 1 knockout myotubes was blocked by reexpression of Homer 1b, but not Homer 1a, and by gene silencing of TRPC1. Moreover, diminished Homer 1 expression in mouse models of Duchenne's muscular dystrophy suggests that loss of Homer 1 scaffolding of TRP channels may contribute to the increased stretch-activated channel activity observed in mdx myofibers. These findings provide direct evidence that Homer 1 functions as an important scaffold for TRP channels and regulates mechanotransduction in skeletal muscle.Mechanosensitive ion channels through their interactions with cytoskeletal proteins link mechanical stimuli such as stretch and changes in osmolarity with signaling pathways. In this way, stretch-activated channel activity is governed by the mechanical properties of the plasma membrane that are established by the underlying cytoskeleton (8). As mechanical forces reach the cytoskeleton, channel activity is increased, setting in motion a series of biochemical events that provide an adaptive response to mechanical stimulation. Increased transient receptor potential (TRP) channel activity has long been associated with pathological features of muscle dystrophy, where a mutation in a dystrophin results in altered membrane integrity and increased stretch-activated channel activity (16,37).Homer proteins are a family of multifaceted scaffolding proteins that enhance signaling efficiency by linking transmembrane proteins with signaling complexes. For example, Homer proteins bind to metabotropic glutamate receptors, clustering them to the postsynaptic density and modulating the excitatory actions of glutamate (1, 34). All Homer proteins share a highly conserved Ena/vasodilator-stimulated phosphoprotein homology 1 (EVH1) domain at their amino termini that allows binding to proline-rich motifs on Homer ligands, which include metabotropic glutamate receptors, inositol 1,4,5-triphosphate receptors (IP3Rs), and several members of the TRP channel family (23,35,43). Constitutively expressed Homer isoforms such as Homer 1b and 1c, in addition to containing an aminoterminal EVH1 domain, also contain a C-terminal coiled-coil domain, allowing Homer proteins to self-multimerize (15). Homer 1a, which was identified as an immediate-early gene, lacks a C-terminal coiled-coil domain and is postulated to function as a dominant negative isoform (10). The different isoforms of Homer genes including the immediate-early gene isoforms are the result of alternat...

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Homer proteins and InsP3 receptors co-localise in the longitudinal sarcoplasmic reticulum of skeletal muscle fibres

Cited by 51 publications

References 32 publications

Microtubule-dependent redistribution of the type-1 inositol 1,4,5-trisphosphate receptor in A7r5 smooth muscle cells

Microtubule-dependent redistribution of the type-1 inositol 1,4,5-trisphosphate receptor in A7r5 smooth muscle cells

Expression, Localization, and Pharmacological Role of K_v7 Potassium Channels in Skeletal Muscle Proliferation, Differentiation, and Survival after Myotoxic Insults

Mice Lacking Homer 1 Exhibit a Skeletal Myopathy Characterized by Abnormal Transient Receptor Potential Channel Activity

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Homer proteins and InsP3 receptors co-localise in the longitudinal sarcoplasmic reticulum of skeletal muscle fibres

Cited by 51 publications

References 32 publications

Microtubule-dependent redistribution of the type-1 inositol 1,4,5-trisphosphate receptor in A7r5 smooth muscle cells

Microtubule-dependent redistribution of the type-1 inositol 1,4,5-trisphosphate receptor in A7r5 smooth muscle cells

Expression, Localization, and Pharmacological Role of Kv7 Potassium Channels in Skeletal Muscle Proliferation, Differentiation, and Survival after Myotoxic Insults

Mice Lacking Homer 1 Exhibit a Skeletal Myopathy Characterized by Abnormal Transient Receptor Potential Channel Activity

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Expression, Localization, and Pharmacological Role of K_v7 Potassium Channels in Skeletal Muscle Proliferation, Differentiation, and Survival after Myotoxic Insults