An RNA-interacting Protein, SYNCRIP (Heterogeneous Nuclear Ribonuclear Protein Q1/NSAP1) Is a Component of mRNA Granule Transported with Inositol 1,4,5-Trisphosphate Receptor Type 1 mRNA in Neuronal Dendrites

IRBIT is a recently identified protein that modulates the activities of both inositol 1,4,5-triphosphate receptor and pancreas-type Na ؉ /HCO 3 ؊ cotransporter 1, and the multisite phosphorylation of IRBIT is required for achieving this modulatory action. Here, we report the identification of the cleavage and polyadenylation specificity factor (CPSF), which is a multi-protein complex involved in 3 processing of mRNA precursors, as an additional binding partner for IRBIT. We found that IRBIT interacted with CPSF and was recruited to an exogenous polyadenylation signal-containing RNA. The main target for IRBIT in CPSF was Fip1 subunit, and the phosphorylation of the serine-rich region of IRBIT was required both for direct association with Fip1 in vitro and for redistribution of Fip1 into the cytoplasm of intact cells. Furthermore, tert-butylhydroquinone (tBHQ), an agent that induces oxidative stress, increased the phosphorylation level of IRBIT in vivo and in parallel enhanced the interaction between IRBIT and CPSF and promoted the cytoplasmic distribution of endogenous Fip1. In addition to CPSF, IRBIT interacted in vitro with poly(A) polymerase (PAP), which is the enzyme recruited by CPSF to elongate the poly(A) tail, and inhibited PAP activity in a phosphorylation-dependent manner. These findings raise the possibility that IRBIT modulates the polyadenylation state of specific mRNAs, both by controlling the cytoplasmic/nuclear partitioning of Fip1 and by inhibiting PAP activity, in response to a stimulus that alters its phosphorylation state.The inositol 1,4,5-triphosphate (IP 3 ) 3 receptors (IP 3 Rs) are IP 3 -gated Ca 2ϩ channels located on intracellular Ca 2ϩ stores. When the cell is exposed to a stimulus, IP 3 is produced as a second messenger and mediates the release of Ca 2ϩ by interacting with IP 3 Rs. We previously identified an IP 3 R-binding protein termed IRBIT (IP 3 R-binding protein released with inositol 1,4,5-triphosphate) that interacts with the IP 3 -binding core domain of IP 3 R and is dissociated from IP 3 R by physiological concentrations of IP 3 (1). IRBIT binds to IP 3 R through its N-terminal phosphorylated region and suppresses IP 3 R activity at the resting state by blocking IP 3 access to IP 3 R. When cells are exposed to a stimulus resulting in high concentration of IP 3 , IP 3 displaces IRBIT and activates IP 3 R. From these findings, it was speculated that IRBIT regulates Ca 2ϩ release by setting the threshold of IP 3 concentration required for activation of IP 3 R (2). Besides its function in the regulation of IP 3 R activity, IRBIT also binds to and activates pancreas-type Na ϩ /HCO 3 Ϫ cotransporter 1 (pNBC1), indicating a role in the regulation of intracellular and extracellular pH (3). Interestingly, although interactions with IP 3 R and pNBC1 each show unique properties, they also share common features, such the requirement of the N-terminal phosphorylated region (2, 3). The finding that IRBIT binds to and regulates both IP 3 R and pNBC1 suggests that IRBIT is a multifunctional...

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“…Immunoprecipitation from the cell lysate and proteomic analysis of the IRBITinteracting proteins was performed as described (20).…”

Section: Methodsmentioning

confidence: 99%

Inositol 1,4,5-Triphosphate Receptor-binding Protein Released with Inositol 1,4,5-Triphosphate (IRBIT) Associates with Components of the mRNA 3′ Processing Machinery in a Phosphorylation-dependent Manner and Inhibits Polyadenylation

Kiefer

Mizutani

Iemura

et al. 2009

Journal of Biological Chemistry

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“…By mass spectrometry, the complex contained ribosomes and proteins involved in the control of protein synthesis [PABP1 (poly(A)-binding protein) and FMRP], cytoskeletal proteins (tubulins, tau, actin, and internexin), cytoskeleton control proteins (IQGAP1, cdc42, and rac1), motor proteins (dynein, kinesin, and myosin), and proteins normally found in the nucleus such as nucleolin and RNA helicase A (Villacé et al, 2004). Bannai et al (2004) reported that SYNCRIP (heterogenous nuclear ribonuclear protein Q1/NSAP1) was transported bidirectionally within dendrites, at a velocity about equivalent to that of Pur␣-containing granules (Kanai et al, 2004). SYNCRIP colocalized in cultured neurons with Staufen1 and the 3Ј-untranslated region of inositol 1,4,5-triphosphate receptor type 1 mRNA, indicating that it is transported as a component of mRNA granules (Bannai et al, 2004) In Drosophila melanogaster oocytes, oskar mRNA is localized to the posterior pole.…”

Section: Mrna-associated Granules and Kinesin Motorsmentioning

confidence: 99%

“…Bannai et al (2004) reported that SYNCRIP (heterogenous nuclear ribonuclear protein Q1/NSAP1) was transported bidirectionally within dendrites, at a velocity about equivalent to that of Pur␣-containing granules (Kanai et al, 2004). SYNCRIP colocalized in cultured neurons with Staufen1 and the 3Ј-untranslated region of inositol 1,4,5-triphosphate receptor type 1 mRNA, indicating that it is transported as a component of mRNA granules (Bannai et al, 2004) In Drosophila melanogaster oocytes, oskar mRNA is localized to the posterior pole. Localization of oskar depends on the kinesin heavy chain (KIF5) and not the KLC, as shown in a KLC null mutant (Brendza et al, 2000).…”

Section: Mrna-associated Granules and Kinesin Motorsmentioning

confidence: 99%

mRNA Transport in Dendrites: RNA Granules, Motors, and Tracks

2006

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The targeting of mRNAs to neuronal dendrites is an important protein sorting mechanism. Recent studies have revealed that mRNAs are transported by molecular motors. The kinesin superfamily protein KIF5 transports mRNAs such as calcium/calmodulin-dependent kinase II␣ (CaMKII␣) and Arc mRNAs along microtubules in large granules containing proteins involved in RNA transport, protein synthesis, RNA helicases, heterogeneous nuclear ribonucleoproteins (hnRNPs), and RNA-associated proteins. This transport is fundamental to local protein synthesis and to the regulation of neuronal function.

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“…Mammalian SYNCRIP/ hnRNPQ is a component of neuronal RNA transport granules that contain CamKIIα, Arc, and IP3R1 mRNAs (Bannai et al 2004;Kanai et al 2004;Elvira et al 2006) and is thought to regulate translation via an interaction with the noncoding RNA BC200/BC1, itself a translational repressor (Duning et al 2008). Moreover, SYNCRIP/hnRNPQ competes with poly(A) binding proteins to inhibit translation in vitro (Svitkin et al 2013) and regulates dendritic morphology (Chen et al 2012) via association with, and localization of, mRNAs encoding components of the Cdc-42/N-WASP/Arp2/3 actin nucleation-promoting complex.…”

Section: Introductionmentioning

confidence: 99%

Drosophila Syncrip modulates the expression of mRNAs encoding key synaptic proteins required for morphology at the neuromuscular junction

McDermott

Halstead

et al. 2014

RNA

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Localized mRNA translation is thought to play a key role in synaptic plasticity, but the identity of the transcripts and the molecular mechanism underlying their function are still poorly understood. Here, we show that Syncrip, a regulator of localized translation in the Drosophila oocyte and a component of mammalian neuronal mRNA granules, is also expressed in the Drosophila larval neuromuscular junction, where it regulates synaptic growth. We use RNA-immunoprecipitation followed by high-throughput sequencing and qRT-PCR to show that Syncrip associates with a number of mRNAs encoding proteins with key synaptic functions, including msp-300, syd-1, neurexin-1, futsch, highwire, discs large, and α-spectrin. The protein levels of MSP-300, Discs large, and a number of others are significantly affected in syncrip null mutants. Furthermore, syncrip mutants show a reduction in MSP-300 protein levels and defects in muscle nuclear distribution characteristic of msp-300 mutants. Our results highlight a number of potential new players in localized translation during synaptic plasticity in the neuromuscular junction. We propose that Syncrip acts as a modulator of synaptic plasticity by regulating the translation of these key mRNAs encoding synaptic scaffolding proteins and other important components involved in synaptic growth and function.

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An RNA-interacting Protein, SYNCRIP (Heterogeneous Nuclear Ribonuclear Protein Q1/NSAP1) Is a Component of mRNA Granule Transported with Inositol 1,4,5-Trisphosphate Receptor Type 1 mRNA in Neuronal Dendrites

Cited by 95 publications

References 55 publications

Inositol 1,4,5-Triphosphate Receptor-binding Protein Released with Inositol 1,4,5-Triphosphate (IRBIT) Associates with Components of the mRNA 3′ Processing Machinery in a Phosphorylation-dependent Manner and Inhibits Polyadenylation

Inositol 1,4,5-Triphosphate Receptor-binding Protein Released with Inositol 1,4,5-Triphosphate (IRBIT) Associates with Components of the mRNA 3′ Processing Machinery in a Phosphorylation-dependent Manner and Inhibits Polyadenylation

mRNA Transport in Dendrites: RNA Granules, Motors, and Tracks

Drosophila Syncrip modulates the expression of mRNAs encoding key synaptic proteins required for morphology at the neuromuscular junction

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