Nuclear and cytoskeletal translocation and localization of heterotrimeric G‐proteins

Willard, Francis S.; Crouch, Michael F.

doi:10.1046/j.1440-1711.2000.00927.x

Cited by 59 publications

(39 citation statements)

References 103 publications

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“…The presence of the AGB1-GFP fusion in the nucleus as well as the plasma membrane is in agreement with previous subcellular fractionation data for the tobacco Gb (Peškan and Oelmüller 2000). These results concur with examples of nuclear associated G-proteins in various mammalian cell types, where they are known to be involved in mitosis and adipogenesis, and may also function in nuclear protein import and phospholipase C/Ca +2 signalling (Willard and Crouch 2000). However, a role for G proteins in plant nuclei is yet to be discovered.…”

Section: Discussionsupporting

confidence: 86%

“…The subcellular location of Gproteins and cognate receptors/effectors may be an additional determinant of signalling specificity. In addition to the plasma membrane, mammalian and other eukaryotic Gproteins are associated with the cytoskeleton, nucleus and endomembranes (Willard and Crouch 2000;Gotta and Ahringer 2001;Simonds et al 2004). Hence, detailed information on the expression and subcellular localization of G-protein subunits and coupled components may be essential for understanding the operation of plant G-proteins in multiple signalling pathways.…”

Section: Introductionmentioning

confidence: 99%

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Expression analysis and subcellular localization of the Arabidopsis thaliana G-protein β-subunit AGB1

Anderson

Botella

2007

Plant Cell Rep

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Heterotrimeric GTP-binding proteins (G-proteins), consisting of Ga, Gb, and Gc subunits, function as molecular switches in many eukaryotic signal transduction pathways. In contrast to many eukaryotes, plants contain very few G-protein subunit isoforms that mediate a diverse array of signalling functions. We investigated the contribution of cell type-specific expression and subcellular localization to this multifunctional signalling capacity for the Arabidopsis thaliana Gb subunit, AGB1. Analysis of AGB1 promoter::b-glucuronidase (GUS) fusions in germinating seeds, seedlings, and flowering plants revealed that AGB1 is widely expressed throughout development in a complex manner. As well as demonstrating similarities to existing Arabidopsis G-protein subunit expression data, several features of the AGB1 expression pattern align closely with known or proposed G-protein functions. A C-terminal AGB1-green fluorescent protein (GFP) fusion was localized at the plasma membrane and in the nucleus of leaf epidermal cells, trichomes and root cells, supporting previous evidence that plant G-protein functionality relies on subcellular compartmentalization.

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Section: Discussionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Expression analysis and subcellular localization of the Arabidopsis thaliana G-protein β-subunit AGB1

Anderson

Botella

2007

Plant Cell Rep

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“…These include phospholipase C isozymes (11,12), nuclear inositol phosphates (12,13), DAG (13), PKC isozymes (14), adenylate cyclase (15), regulators of G protein signaling (RGS proteins; Refs. 16 and 17) as well as heterotrimeric G proteins themselves (18). These observations raise the possibility that plasma membrane-based signaling components may also serve a similar function at nuclear membranes.…”

Section: Changes In Nuclear Camentioning

confidence: 92%

Activation of Metabotropic Glutamate Receptor mGlu5 on Nuclear Membranes Mediates Intranuclear Ca2+ Changes in Heterologous Cell Types and Neurons

O’Malley

Jong

Gonchar

et al. 2003

Journal of Biological Chemistry

120

116

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Nuclear Ca2؉ plays a critical role in many cellular functions although its mode (s) of regulation is unclear. This study shows that the metabotropic glutamate receptor, mGlu5, mobilizes nuclear Ca 2؉ independent of cytosolic Ca 2؉ regulation. Immunocytochemical, ultrastructural, and subcellular fractionation techniques revealed that the metabotropic glutamate receptor, mGlu5, can be localized to nuclear membranes in heterologous cells as well as midbrain and cortical neurons. Changes in nuclear Ca2ϩ play an integral role in cellular functions such as protein import, apoptosis, and gene transcription (1, 2). Nuclear Ca 2ϩ may be generated from a number of sources including diffusion of cytosolic Ca 2ϩ waves through nuclear pore complexes (2). Because the outer nuclear envelope is continuous with the endoplasmic reticulum, which serves as an internal store of Ca 2ϩ , rises in nuclear Ca 2ϩ may also be attributable to a luminal source (3). Recent studies using high speed imaging of intracellular Ca 2ϩ have shown that waves of Ca 2ϩ can invade the nucleus by emptying intracellular stores (4). Calcium release from internal stores is controlled by various channels including the inositol 1,4,5-trisphosphate (IP 3 ) 1 receptor and ryanodine receptor families (5, 6) both of which are present on nuclear membranes (7,8). Calcium itself is an activator of these channels (1) although nuclear IP 3 can stimulate IP 3 receptors located on the inner nuclear membrane and cADP ribose has been shown to activate nuclear ryanodine receptors (7,8). Luminal Ca 2ϩ is refilled at least in part by the nuclear Ca 2ϩ -ATPase (9, 10) located on the outer nuclear membrane. Thus, although signals originating at the plasma membrane may be transmitted to the nucleus (4), the presence of specific Ca 2ϩ transporters on the nuclear envelope argues for a nuclear Ca 2ϩ regulatory system that may be independent of cytosolic Ca 2ϩ regulation. Many components of G protein signaling pathways are also found in the nucleus or associated with nuclear membranes. These include phospholipase C isozymes (11, 12), nuclear inositol phosphates (12, 13), DAG (13), PKC isozymes (14), adenylate cyclase (15), regulators of G protein signaling (RGS proteins; Refs. 16 and 17) as well as heterotrimeric G proteins themselves (18). These observations raise the possibility that plasma membrane-based signaling components may also serve a similar function at nuclear membranes. Indeed, several recent reports are consistent with the notion that nuclear G protein-coupled receptors directly modulate nuclear signal transduction pathways. For example, angiotensin II receptors were found on hepatocyte nuclear membranes (19), opioid binding sites were described on ventricular myocardial nuclei (20) and endothelin-1 receptors were reported on vascular smooth muscle nuclear membranes (21). Direct evidence of nuclear receptor G protein signaling has also been demonstrated for prostaglandin receptors which, when stimulated, cause rapid Ca 2ϩ influx into the nucleus (22,23). Taken togeth...

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“…In the case of the βARs, functional β 1 AR and β 3 AR, but not the β 2 AR, have been detected at the level of the nuclear membrane in rat and mouse adult ventricular myocytes [8]. Moreover, several studies have demonstrated that a number of their normal cell surface interactors, including Gα s , Gα i , Gα q , adenylyl cyclase, and PKA, as well as other regulatory molecules known to interact with GPCRs, are also associated with the nucleus or the nuclear membrane [9,10]. In fact, literature even seems to support the existence of nuclear-localized phosphoinositide signalling pathways that can regulate nuclear PKB/Akt signalling [11].…”

Section: Introductionmentioning

confidence: 99%

Nuclear β-adrenergic receptors modulate gene expression in adult rat heart

Vaniotis

Duca

Trieu

et al. 2011

Cellular Signalling

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Both β 1 -and β 3 -adrenergic receptors (β 1 ARs and β 3 ARs) are present on nuclear membranes in adult ventricular myocytes. These nuclear-localized receptors are functional with respect to ligand binding and effector activation. In isolated cardiac nuclei, the non-selective βAR agonist isoproterenol stimulated de novo RNA synthesis measured using assays of transcription initiation (Boivin et al., 2006 Cardiovasc Res. 71:69-78). In contrast, stimulation of endothelin receptors, another G protein-coupled receptor (GPCR) that localizes to the nuclear membrane, resulted in decreased RNA synthesis. To investigate the signalling pathway(s) involved in GPCR-mediated regulation of RNA synthesis, nuclei were isolated from intact adult rat hearts and treated with receptor agonists in the presence or absence of inhibitors of different mitogen-activated protein kinase (MAPK) and PI3K/PKB pathways. Components of p38, JNK, and ERK1/2 MAP kinase cascades as well as PKB were detected in nuclear preparations. Inhibition of PKB with triciribine, in the presence of isoproterenol, converted the activation of the βAR from stimulatory to inhibitory with regards to RNA synthesis, while ERK1/2, JNK and p38 inhibition reduced both basal and isoproterenol-stimulated activity. Analysis by qPCR indicated an increase in the expression of 18 S rRNA following isoproterenol treatment and a decrease in NFκB mRNA. Further qPCR experiments revealed that isoproterenol treatment also reduced the expression of several other genes involved in the activation of NFκB, while ERK1/2 and PKB inhibition substantially * Corresponding authors. Hébert is to be contacted

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Nuclear and cytoskeletal translocation and localization of heterotrimeric G‐proteins

Cited by 59 publications

References 103 publications

Expression analysis and subcellular localization of the Arabidopsis thaliana G-protein β-subunit AGB1

Expression analysis and subcellular localization of the Arabidopsis thaliana G-protein β-subunit AGB1

Activation of Metabotropic Glutamate Receptor mGlu5 on Nuclear Membranes Mediates Intranuclear Ca2+ Changes in Heterologous Cell Types and Neurons

Nuclear β-adrenergic receptors modulate gene expression in adult rat heart

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