Rho proteins are localized with different membrane compartments involved in vesicular trafficking in anterior pituitary cells

Cussac, Daniel; Leblanc, Pierre; L'Héritier, A.; Bertoglio, Jacques; Lang, Paul; Kordon, C.; Enjalbert, A; Saltarelli, Danièle

doi:10.1016/0303-7207(96)03814-2

Cited by 29 publications

(19 citation statements)

References 64 publications

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“…We found that a 21-kDa substrate of C3 toxin is specifically associated with the membrane of purified secretory chromaffin granules. Accordingly, the presence of C3 substrates in granule-enriched fractions has been previously described in neutrophils (50) and anterior pituitary cells (51). In the present study, we demonstrate by confocal immunocytochemistry the colocalization of RhoA with the chromaffin granule marker chromogranin A, further confirming the specific association of RhoA with the lipids were extracted and separated on TLC plates.…”

Section: Discussionsupporting

confidence: 71%

Identification of a Potential Effector Pathway for the Trimeric Go Protein Associated with Secretory Granules

Gasman

Chasserot‐Golaz

Hubert

et al. 1998

Journal of Biological Chemistry

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Besides having a role in signal transduction, heterotrimeric G proteins may be involved in membrane trafficking events. In chromaffin cells, G o is associated with secretory organelles, and its activation inhibits the ATPdependent priming of exocytosis. By using permeabilized cells, we previously described that the control exerted by the granule-bound G o on exocytosis may be related to effects on the cortical actin network through a sequence possibly involving Rho. To provide further insight into the function of Rho in exocytosis, we focus here on its intracellular localization in chromaffin cells. By immunoreplica analysis, immunoprecipitation, and confocal immunofluorescence, we found that RhoA is specifically associated with the membrane of secretory chromaffin granules. Parallel subcellular fractionation experiments revealed the occurrence of a mastoparanstimulated phosphatidylinositol 4-kinase activity in purified chromaffin granule membranes. This stimulatory effect of mastoparan was mimicked by GAP-43, an activator of the granule-associated G o , and specifically inhibited by antibodies against G␣ o . In addition, Clostridium botulinum C3 exoenzyme completely blocked the activation of phosphatidylinositol 4-kinase by mastoparan. We propose that the control exerted by G o on peripheral actin and exocytosis is related to the activation of a downstream RhoA-dependent phosphatidylinositol 4-kinase associated with the membrane of secretory granules.Studies on diverse secretory cell types have established a crucial role for GTP-binding proteins in the regulation of calcium-dependent exocytosis. Trimeric G proteins have been found associated with the membrane of various secretory granules (1-3), suggesting their participation in the exocytotic reaction. Accordingly, the involvement of a plasma membranebound G i3 protein in the late stages of exocytosis in mast cells has been demonstrated (4). Direct control of exocytosis by G i and G o proteins has also been described in insulin-secreting cells (5) and in chromaffin cells (3, 6 -9). Besides heterotrimeric G proteins, a subset of small GTPases appears to control the exocytotic reaction. Rab3 and the ADP-ribosylation factor 6 which are specifically localized on secretory vesicles (10,11) have been proposed to serve as a regulator of the exocytotic fusion in chromaffin cells (12, 13), anterior pituitary cells (14), and melanotrophs (15). In addition, recent investigations led to the idea that Rho may be a component of the molecular machinery underlying regulated secretion (16 -20).Rho belongs to the GTPase family consisting of Rho, Rac, and Cdc 42 proteins. This family has been implicated in a number of cellular functions requiring the reorganization of actin-based structures (21-23). In secretory cells, cytoskeletal rearrangements are a prerequisite for exocytosis since actin forms a cortical barrier that must be reorganized to enable docking and/or fusion of the secretory granules with the plasma membrane (24 -26). Rho together with a trimeric G protein regulate...

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Section: Discussionsupporting

confidence: 71%

Identification of a Potential Effector Pathway for the Trimeric Go Protein Associated with Secretory Granules

Gasman

Chasserot‐Golaz

Hubert

et al. 1998

Journal of Biological Chemistry

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“…The first model suggests that Dia1 nascent peptide interacts with Rho-GTP, which is bound to the ER membrane, thereby tethering the mRNA-ribosome complex on the ER. This is supported by the observations that Rho can bind to membrane structures, including the ER (Cussac et al, 1996;Ridley, 2006), and that RhoA can be enriched and activated in the perinuclear region of a variety of cell types (Gadea et al, 2007;Liu and Horowitz, 2006;Picard et al, 2009;Su et al, 2009) (Fig. 7F-H).…”

Section: Discussionsupporting

confidence: 66%

“…Overall, the DRFs are distributed uniformly throughout the cell and, in some instances, are concentrated at the cell periphery (Watanabe et al, 1997;Westendorf et al, 1999). DRFs can be found on membrane structures, presumably through their binding to Rho GTPases that associate with membranes (Cussac et al, 1996;Ridley, 2006), or through a Rho-independent mechanism (Seth et al, 2006). The intracellular distribution of mRNA for the DRFs is unknown.…”

Section: Introductionmentioning

confidence: 99%

An RNA-zipcode-independent mechanism that localizesDia1mRNA to the perinuclear ER through interactions between Dia1 nascent peptide and Rho–GTP

Liao

Liu

2011

Journal of Cell Science

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Signal-peptide-mediated ER localization of mRNAs encoding for membrane and secreted proteins, and RNA-zipcode-mediated intracellular targeting of mRNAs encoding for cytosolic proteins are two well-known mechanisms for mRNA localization. Here, we report a previously unidentified mechanism by which mRNA encoding for Dia1, a cytosolic protein without the signal peptide, is localized to the perinuclear ER in an RNA-zipcode-independent manner in fibroblasts. Dia1 mRNA localization is also independent of the actin and microtubule cytoskeleton but requires translation and the association of Dia1 nascent peptide with the ribosome–mRNA complex. Sequence mapping suggests that interactions of the GTPase binding domain of Dia1 peptide with active Rho are important for Dia1 mRNA localization. This mechanism can override the β-actin RNA zipcode and redirect β-actin mRNA to the perinuclear region, providing a new way to manipulate intracellular mRNA localization.

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“…Recent evidence also suggests a close link between Rab-mediated vesicle docking and actin-and microtubule-based cytoskeleton reorganization (43). Other examples of interactions between exocytosis and cytoskeletal proteins include (i) regulation of secretory granule exocytosis by RhoA and/or RhoC proteins in anterior pituitary cells (12), (ii) stabilization of the neuronal cytoskeleton by Rab3 (3), and (iii) interaction of Rab3A-binding protein rabphilin with alpha-actinin, an actin-binding protein (26). Since vesicle transport involves passing through cytoskeleton barriers, our results raise the possibility that HRG treatment-associated reorganization of cytoskeletal structures plays a role in making mammary epithelial cells competent for regulated exocytosis.…”

Section: Discussionmentioning

confidence: 99%

Evidence of Rab3A Expression, Regulation of Vesicle Trafficking, and Cellular Secretion in Response to Heregulin in Mammary Epithelial Cells

Vadlamudi

Wang

Talukder

et al. 2000

Molecular and Cellular Biology

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Rho proteins are localized with different membrane compartments involved in vesicular trafficking in anterior pituitary cells

Cited by 29 publications

References 64 publications

Identification of a Potential Effector Pathway for the Trimeric Go Protein Associated with Secretory Granules

Identification of a Potential Effector Pathway for the Trimeric Go Protein Associated with Secretory Granules

An RNA-zipcode-independent mechanism that localizesDia1mRNA to the perinuclear ER through interactions between Dia1 nascent peptide and Rho–GTP

Evidence of Rab3A Expression, Regulation of Vesicle Trafficking, and Cellular Secretion in Response to Heregulin in Mammary Epithelial Cells

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