V‐ATPase deactivation in blowfly salivary glands is mediated by protein phosphatase 2C

Voß, Martin; Blenau, Wolfgang; Baumann, Otto

doi:10.1002/arch.20310

Cited by 7 publications

(4 citation statements)

References 26 publications

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“…However, the molecular basis of their effects on V-ATPase assembly state is generally not well-understood. In insect cells, phosphorylation of a specific V-ATPase subunit, subunit C, been directly associated with reassembly, but this may be the only case where direct modification of a V-ATPase subunit correlates with assembly state ( Voss et al, 2007 , 2009 ).…”

Section: V-atpases and Their Regulation By Reversible Disassemblymentioning

confidence: 99%

RAVE and Rabconnectin-3 Complexes as Signal Dependent Regulators of Organelle Acidification

Jaskolka

Winkley

Kane

2021

Front. Cell Dev. Biol.

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The yeast RAVE (Regulator of H+-ATPase of Vacuolar and Endosomal membranes) complex and Rabconnectin-3 complexes of higher eukaryotes regulate acidification of organelles such as lysosomes and endosomes by catalyzing V-ATPase assembly. V-ATPases are highly conserved proton pumps consisting of a peripheral V1 subcomplex that contains the sites of ATP hydrolysis, attached to an integral membrane Vo subcomplex that forms the transmembrane proton pore. Reversible disassembly of the V-ATPase is a conserved regulatory mechanism that occurs in response to multiple signals, serving to tune ATPase activity and compartment acidification to changing extracellular conditions. Signals such as glucose deprivation can induce release of V1 from Vo, which inhibits both ATPase activity and proton transport. Reassembly of V1 with Vo restores ATP-driven proton transport, but requires assistance of the RAVE or Rabconnectin-3 complexes. Glucose deprivation triggers V-ATPase disassembly in yeast and is accompanied by binding of RAVE to V1 subcomplexes. Upon glucose readdition, RAVE catalyzes both recruitment of V1 to the vacuolar membrane and its reassembly with Vo. The RAVE complex can be recruited to the vacuolar membrane by glucose in the absence of V1 subunits, indicating that the interaction between RAVE and the Vo membrane domain is glucose-sensitive. Yeast RAVE complexes also distinguish between organelle-specific isoforms of the Vo a-subunit and thus regulate distinct V-ATPase subpopulations. Rabconnectin-3 complexes in higher eukaryotes appear to be functionally equivalent to yeast RAVE. Originally isolated as a two-subunit complex from rat brain, the Rabconnectin-3 complex has regions of homology with yeast RAVE and was shown to interact with V-ATPase subunits and promote endosomal acidification. Current understanding of the structure and function of RAVE and Rabconnectin-3 complexes, their interactions with the V-ATPase, their role in signal-dependent modulation of organelle acidification, and their impact on downstream pathways will be discussed.

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Section: V-atpases and Their Regulation By Reversible Disassemblymentioning

confidence: 99%

RAVE and Rabconnectin-3 Complexes as Signal Dependent Regulators of Organelle Acidification

Jaskolka

Winkley

Kane

2021

Front. Cell Dev. Biol.

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“…However, Dechant et al have presented conflicting results indicating that protein kinase A activation is downstream of V-ATPase assembly [78]. At the level of the V-ATPase itself, no post-translational modifications in the yeast enzyme have been definitively associated with reversible disassembly, although there is evidence of phosphorylation of the V 1 C subunit in insect cells under conditions of reassembly [92,93]. The connection between V-ATPase assembly and activity and glucose levels remains an important and incompletely understood question, and recent evidence linking the V-ATPase to nutritional sensing and growth control have only increased its importance [94,78,95] (see Section 5).…”

Section: The Plasma Membrane H+-pump Pma1 and Organellar V-atpasesmentioning

confidence: 99%

Proton Transport and pH Control in Fungi

Kane

2016

Advances in Experimental Medicine and Biology

101

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Despite diverse and changing extracellular environments, fungi maintain a relatively constant cytosolic pH and numerous organelles of distinct lumenal pH. Key players in fungal pH control are V-ATPases and the P-type proton pump Pma1. These two proton pumps act in concert with a large array of other transporters and are highly regulated. The activities of Pma1 and the V-ATPaseare coordinated under some conditions, suggesting that pH in the cytosol and organelles is not controlled independently. Genomic studies, particularly in the highly tractable S. cerevisiae, are beginning to provide a systems-level view of pH control, including transcriptional responses to acid or alkaline ambient pH and definition of the full set of regulators required to maintain pH homeostasis. Genetically encoded pH sensors have provided new insights into localized mechanisms of pH control, as well as highlighting the dynamic nature of pH responses to the extracellular environment. Recent studies indicate that cellular pH plays a genuine signaling role that connects nutrient availability and growth rate through a number of mechanisms. Many of the pH control mechanisms found in S. cerevisiae are shared with other fungi, with adaptations for their individual physiological contexts. Fungi deploy certain proton transport and pH control mechanisms not shared with other eukaryotes; these regulators of cellular pH are potential antifungal targets. This re view describes current and emerging knowledge proton transport and pH control mechanisms in S. cerevisiae and briefly discusses how these mechanisms vary among fungi.

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“…On the basis of this hypothesis, we have sought the respective Ser/Thr protein phosphatase(s) in blowfly salivary glands and have obtained evidence that a protein phosphatase 2C is involved in this task (46). During these experiments, however, we have made the unexpected and puzzling observation that the inhibition of protein phosphatase 2B, also called calcineurin, reduces or abolishes the 5-HT-induced V-ATPase activity, indicating that this protein phosphatase is involved in the activation rather than in the inactivation of V-ATPase.…”

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confidence: 99%

Calcineurin activity augments cAMP/PKA-dependent activation of V-ATPase in blowfly salivary glands

Voß

Fechner

Baumann

2010

American Journal of Physiology-Cell Physiology

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We have examined the role of the Ca(2+)-dependent protein phosphatase 2B (calcineurin) in the regulation of the vacuolar H(+)-ATPase (V-ATPase) in blowfly salivary glands. In response to the neurohormone serotonin [5-hydroxytryptamine (5-HT)] and under the mediation of the cAMP/PKA signaling pathway, the secretory cells assemble and activate V-ATPase molecules at the apical membrane. We demonstrate that the inhibition of calcineurin activity by cyclosporin A, by FK-506, or by prevention of the elevation of Ca(2+) diminishes the 5-HT-induced assembly and activation of V-ATPase. The effect of calcineurin on V-ATPase is mediated by the cAMP/PKA signaling pathway, with calcineurin acting upstream of PKA, because 1) cyclosporin A does not influence the 8-(4-chlorophenylthio)adenosine-3',5'-cyclic monophosphate (8-CPT-cAMP)-induced activation of V-ATPase, and 2) the 5-HT-induced rise in cAMP is highly reduced in the presence of cyclosporin A. Moreover, a Ca(2+) rise evoked by the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) inhibitor cyclopiazonic acid leads to an increase in intracellular cAMP concentration and a calcineurin-mediated PKA-dependent activation of V-ATPase. We propose that calcineurin activity mediates cross talk between the inositol 1,4,5-trisphosphate/Ca(2+) and the cAMP/PKA signaling pathways, thereby augmenting the 5-HT-induced rise in cAMP and thus the cAMP/PKA-mediated activation of V-ATPase.

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V‐ATPase deactivation in blowfly salivary glands is mediated by protein phosphatase 2C

Cited by 7 publications

References 26 publications

RAVE and Rabconnectin-3 Complexes as Signal Dependent Regulators of Organelle Acidification

RAVE and Rabconnectin-3 Complexes as Signal Dependent Regulators of Organelle Acidification

Proton Transport and pH Control in Fungi

Calcineurin activity augments cAMP/PKA-dependent activation of V-ATPase in blowfly salivary glands

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