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Kovshova T, Mantrov S, Boiko S, Malinovskaya J, Merkulova M, Osipova N, Moiseeva N, Akimov M, Dudina P, Senchikhin I, Ermolenko Y, Gelperina S. Co-delivery of paclitaxel and etoposide prodrug by human serum albumin and PLGA nanoparticles: synergistic cytotoxicity in brain tumour cells. J Microencapsul 2023; 40:246-262. [PMID: 36880479 DOI: 10.1080/02652048.2023.2188943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
The aims of this study were to develop co-delivery systems of paclitaxel (PTX) and etoposide prodrug (4'-O-benzyloxycarbonyl-etoposide, ETP-cbz) based on non-cross-linked human serum albumin (HSA) and poly(lactide-co-glycolide) nanoparticles and to evaluate the synergistic potential of these drugs in vitro. The nanoformulations were prepared by the high-pressure homogenisation technique and characterised using DLS, TEM, SEM, AFM, HPLC, CZE, in-vitro release, and cytotoxicity in human and murine glioma cells. All nanoparticles had 90-150 nm in size and negative ζ-potentials. The Neuro2A cells were the most sensitive to both HSA- and PLGA-based co-delivery systems (IC50 0.024 µM and 0.053 µM, respectively). The drugs' synergistic effect (combination index < 0.9) was observed in the GL261 cells for both types of co-delivery formulations and in the Neuro2A cells for the HSA-based system. These nanodelivery systems may be useful to improve combination chemotherapy for brain tumour treatment. To our knowledge, this is the first report describing the non-cross-linked HSA-based co-delivery nanosuspension which was prepared using nab™ technology.
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Affiliation(s)
- Tatyana Kovshova
- D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia
| | - Sergey Mantrov
- D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia
| | - Svetlana Boiko
- D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia
| | - Julia Malinovskaya
- D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia
| | - Maria Merkulova
- D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia
| | - Nadezhda Osipova
- D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia
| | - Natalia Moiseeva
- N.N. Blokhin National Medical Research Center of Oncology, Moscow, Russia
| | - Mikhail Akimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, Russia
| | - Polina Dudina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, Russia
| | - Ivan Senchikhin
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia
| | - Yulia Ermolenko
- D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia
| | - Svetlana Gelperina
- D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia
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Eaton AF, Merkulova M, Brown D. V‐ATPase Domain Assembly is Increased in Ncoa7 KO Mice. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r5675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Dennis Brown
- NephrologyMassachusetts General HospitalBostonMA
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Eaton AF, Brown D, Merkulova M. Author Correction: The evolutionary conserved TLDc domain defines a new class of (H +)V-ATPase interacting proteins. Sci Rep 2021; 11:23481. [PMID: 34848813 PMCID: PMC8633271 DOI: 10.1038/s41598-021-02955-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- A F Eaton
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - D Brown
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - M Merkulova
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA. .,Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Simches Research Center, 128 Cambridge St., Boston, MA, 02114, USA.
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Eaton AF, Brown D, Merkulova M. The evolutionary conserved TLDc domain defines a new class of (H +)V-ATPase interacting proteins. Sci Rep 2021; 11:22654. [PMID: 34811399 PMCID: PMC8608904 DOI: 10.1038/s41598-021-01809-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 11/02/2021] [Indexed: 01/26/2023] Open
Abstract
We recently found that nuclear receptor coactivator 7 (Ncoa7) and Oxr1 interact with the proton-pumping V-ATPase. Ncoa7 and Oxr1 belong to a group of proteins playing a role in the oxidative stress response, that contain the conserved “TLDc” domain. Here we asked if the three other proteins in this family, i.e., Tbc1d24, Tldc1 and Tldc2 also interact with the V-ATPase and if the TLDc domains are involved in all these interactions. By co-immunoprecipitation, endogenous kidney Tbc1d24 (and Ncoa7 and Oxr1) and overexpressed Tldc1 and Tldc2, all interacted with the V-ATPase. In addition, purified TLDc domains of Ncoa7, Oxr1 and Tldc2 (but not Tbc1d24 or Tldc1) interacted with V-ATPase in GST pull-downs. At the amino acid level, point mutations G815A, G845A and G896A in conserved regions of the Ncoa7 TLDc domain abolished interaction with the V-ATPase, and S817A, L926A and E938A mutations resulted in decreased interaction. Furthermore, poly-E motifs upstream of the TLDc domain in Ncoa7 and Tldc2 show a (nonsignificant) trend towards enhancing the interaction with V-ATPase. Our principal finding is that all five members of the TLDc family of proteins interact with the V-ATPase. We conclude that the TLDc motif defines a new class of V-ATPase interacting regulatory proteins.
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Affiliation(s)
- A F Eaton
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - D Brown
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - M Merkulova
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA. .,Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Simches Research Center, 128 Cambridge St., Boston, MA, 02114, USA.
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Eaton A, Merkulova M, Brown D. The Evolutionarily Conserved TLDc Domain Defines a New Class of V‐ATPase Interacting Proteins. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.04240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Amity Eaton
- NephrologyMassachusetts General HospitalBostonMA
| | | | - Dennis Brown
- NephrologyMassachusetts General HospitalBostonMA
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Abstract
A primary function of the H+-ATPase (or V-ATPase) is to create an electrochemical proton gradient across eukaryotic cell membranes, which energizes fundamental cellular processes. Its activity allows for the acidification of intracellular vesicles and organelles, which is necessary for many essential cell biological events to occur. In addition, many specialized cell types in various organ systems such as the kidney, bone, male reproductive tract, inner ear, olfactory mucosa, and more, use plasma membrane V-ATPases to perform specific activities that depend on extracellular acidification. It is, however, increasingly apparent that V-ATPases are central players in many normal and pathophysiological processes that directly influence human health in many different and sometimes unexpected ways. These include cancer, neurodegenerative diseases, diabetes, and sensory perception, as well as energy and nutrient-sensing functions within cells. This review first covers the well-established role of the V-ATPase as a transmembrane proton pump in the plasma membrane and intracellular vesicles and outlines factors contributing to its physiological regulation in different cell types. This is followed by a discussion of the more recently emerging unconventional roles for the V-ATPase, such as its role as a protein interaction hub involved in cell signaling, and the (patho)physiological implications of these interactions. Finally, the central importance of endosomal acidification and V-ATPase activity on viral infection will be discussed in the context of the current COVID-19 pandemic.
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Affiliation(s)
- Amity F Eaton
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Maria Merkulova
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Dennis Brown
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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Battistone MA, Merkulova M, Park Y, Peralta MA, Gombar F, Brown D, Breton S. Unravelling purinergic regulation in the epididymis: activation of V-ATPase-dependent acidification by luminal ATP and adenosine. J Physiol 2019; 597:1957-1973. [PMID: 30746715 PMCID: PMC6441927 DOI: 10.1113/jp277565] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 01/29/2019] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS In the epididymis, elaborate communication networks between epithelial cells are important with respect to establishing an optimal acidic luminal environment for the maturation and storage of spermatozoa, which is essential for male fertility. Proton secretion by epididymal clear cells is achieved via the proton pumping V-ATPase located in their apical membrane. In the present study, we dissect the molecular mechanisms by which clear cells respond to luminal ATP and adenosine to modulate their acidifying activity via the adenosine receptor ADORA2B and the pH-sensitive ATP receptor P2X4. We demonstrate that the hydrolysis of ATP to produce adenosine by ectonucleotidases plays a key role in V-ATPase-dependent proton secretion, and is part of a feedback loop that ensures acidification of the luminal compartment These results help us better understand how professional proton-secreting cells respond to extracellular cues to modulate their functions, and how they communicate with neighbouring cells. ABSTRACT Cell-cell cross-talk is crucial for the dynamic function of epithelia, although how epithelial cells detect and respond to variations in extracellular stimuli to modulate their environment remains incompletely understood. In the present study, we used the epididymis as a model system to investigate epithelial cell regulation by luminal factors. In the epididymis, elaborate communication networks between the different epithelial cell types are important for establishing an optimal acidic luminal environment for the maturation and storage of spermatozoa. In particular, clear cells (CCs) secrete protons into the lumen via the proton pumping V-ATPase located in their apical membrane, a process that is activated by luminal alkalinization. However, how CCs detect luminal pH variations to modulate their function remains uncharacterized. Purinergic regulation of epithelial transport is modulated by extracellular pH in other tissues. In the present study, functional analysis of the mouse cauda epididymis perfused in vivo showed that luminal ATP and adenosine modulate the acidifying activity of CCs via the purinergic ADORA2B and P2X4 receptors, and that luminal adenosine content is itself regulated by luminal pH. Altogether, our observations illustrate mechanisms by which CCs are activated by pH sensitive P2X4 receptor and ectonucleotidases, providing a feedback mechanism for the maintenance of luminal pH. These novel mechanisms by which professional proton-secreting cells respond to extracellular cues to modulate their functions, as well as how they communicate with neighbouring cells, might be translatable to other acidifying epithelia.
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Affiliation(s)
- Maria A. Battistone
- Program in Membrane Biology, Center for System Biology, Nephrology Division, Department of MedicineMassachusetts General Hospital, Harvard Medical SchoolBostonMAUSA
| | - Maria Merkulova
- Program in Membrane Biology, Center for System Biology, Nephrology Division, Department of MedicineMassachusetts General Hospital, Harvard Medical SchoolBostonMAUSA
| | - Yoo‐Jin Park
- Program in Membrane Biology, Center for System Biology, Nephrology Division, Department of MedicineMassachusetts General Hospital, Harvard Medical SchoolBostonMAUSA
| | - Maria A. Peralta
- Program in Membrane Biology, Center for System Biology, Nephrology Division, Department of MedicineMassachusetts General Hospital, Harvard Medical SchoolBostonMAUSA
| | - Flavia Gombar
- Program in Membrane Biology, Center for System Biology, Nephrology Division, Department of MedicineMassachusetts General Hospital, Harvard Medical SchoolBostonMAUSA
| | - Dennis Brown
- Program in Membrane Biology, Center for System Biology, Nephrology Division, Department of MedicineMassachusetts General Hospital, Harvard Medical SchoolBostonMAUSA
| | - Sylvie Breton
- Program in Membrane Biology, Center for System Biology, Nephrology Division, Department of MedicineMassachusetts General Hospital, Harvard Medical SchoolBostonMAUSA
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Merkulova M, Păunescu TG, Nair AV, Wang CY, Capen DE, Oliver PL, Breton S, Brown D. Targeted deletion of the Ncoa7 gene results in incomplete distal renal tubular acidosis in mice. Am J Physiol Renal Physiol 2018; 315:F173-F185. [PMID: 29384414 DOI: 10.1152/ajprenal.00407.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We recently reported that nuclear receptor coactivator 7 (Ncoa7) is a vacuolar proton pumping ATPase (V-ATPase) interacting protein whose function has not been defined. Ncoa7 is highly expressed in the kidney and partially colocalizes with the V-ATPase in collecting duct intercalated cells (ICs). Here, we hypothesized that targeted deletion of the Ncoa7 gene could affect V-ATPase activity in ICs in vivo. We tested this by analyzing the acid-base status, major electrolytes, and kidney morphology of Ncoa7 knockout (KO) mice. We found that Ncoa7 KO mice, similar to Atp6v1b1 KOs, did not develop severe distal renal tubular acidosis (dRTA), but they exhibited a persistently high urine pH and developed hypobicarbonatemia after acid loading with ammonium chloride. Conversely, they did not develop significant hyperbicarbonatemia and alkalemia after alkali loading with sodium bicarbonate. We also found that ICs were larger and with more developed apical microvilli in Ncoa7 KO compared with wild-type mice, a phenotype previously associated with metabolic acidosis. At the molecular level, the abundance of several V-ATPase subunits, carbonic anhydrase 2, and the anion exchanger 1 was significantly reduced in medullary ICs of Ncoa7 KO mice, suggesting that Ncoa7 is important for maintaining high levels of these proteins in the kidney. We conclude that Ncoa7 is involved in IC function and urine acidification in mice in vivo, likely through modulating the abundance of V-ATPase and other key acid-base regulators in the renal medulla. Consequently, mutations in the NCOA7 gene may also be involved in dRTA pathogenesis in humans.
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Affiliation(s)
- Maria Merkulova
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts
| | - Teodor G Păunescu
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts
| | - Anil V Nair
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts
| | - Chia-Yu Wang
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts
| | - Diane E Capen
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts
| | - Peter L Oliver
- Department of Physiology, Anatomy and Genetics, University of Oxford , Oxford , United Kingdom
| | - Sylvie Breton
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts
| | - Dennis Brown
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts
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9
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Abstract
The vacuolar H+ ATPase (V-ATPase) is a complex multisubunit machine that regulates important cellular processes through controlling acidity of intracellular compartments in eukaryotes. Existing small-molecule modulators of V-ATPase either are restricted to targeting one membranous subunit of V-ATPase or have poorly understood mechanisms of action. Small molecules with novel and defined mechanisms of inhibition are thus needed to functionally characterize V-ATPase and to fully evaluate the therapeutic relevance of V-ATPase in human diseases. We have discovered electrophilic quinazolines that covalently modify a soluble catalytic subunit of V-ATPase with high potency and exquisite proteomic selectivity as revealed by fluorescence imaging and chemical proteomic activity-based profiling. The site of covalent modification was mapped to a cysteine residue located in a region of V-ATPase subunit A that is thought to regulate the dissociation of V-ATPase. We further demonstrate that a previously reported V-ATPase inhibitor, 3-bromopyruvate, also targets the same cysteine residue and that our electrophilic quinazolines modulate the function of V-ATPase in cells. With their well-defined mechanism of action and high proteomic specificity, the described quinazolines offer a powerful set of chemical probes to investigate the physiological and pathological roles of V-ATPase.
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Affiliation(s)
| | - Keriann M Backus
- Department of Chemical Physiology, The Scripps Research Institute , La Jolla, California 92307, United States
| | - Maria Merkulova
- MGH Center for Systems Biology, Program in Membrane Biology & Division of Nephrology, Richard B. Simches Research Center, Massachusetts General Hospital and Department of Medicine, Harvard Medical School , Boston, Massachusetts 02114, United States
| | | | - Dennis Brown
- MGH Center for Systems Biology, Program in Membrane Biology & Division of Nephrology, Richard B. Simches Research Center, Massachusetts General Hospital and Department of Medicine, Harvard Medical School , Boston, Massachusetts 02114, United States
| | - Benjamin F Cravatt
- Department of Chemical Physiology, The Scripps Research Institute , La Jolla, California 92307, United States
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Canali S, Core AB, Zumbrennen-Bullough KB, Merkulova M, Wang CY, Schneyer AL, Pietrangelo A, Babitt JL. Activin B Induces Noncanonical SMAD1/5/8 Signaling via BMP Type I Receptors in Hepatocytes: Evidence for a Role in Hepcidin Induction by Inflammation in Male Mice. Endocrinology 2016; 157:1146-62. [PMID: 26735394 PMCID: PMC4769363 DOI: 10.1210/en.2015-1747] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Induction of the iron regulatory hormone hepcidin contributes to the anemia of inflammation. Bone morphogenetic protein 6 (BMP6) signaling is a central regulator of hepcidin expression in the liver. Recently, the TGF-β/BMP superfamily member activin B was implicated in hepcidin induction by inflammation via noncanonical SMAD1/5/8 signaling, but its mechanism of action and functional significance in vivo remain uncertain. Here, we show that low concentrations of activin B, but not activin A, stimulate prolonged SMAD1/5/8 signaling and hepcidin expression in liver cells to a similar degree as canonical SMAD2/3 signaling, and with similar or modestly reduced potency compared with BMP6. Activin B stimulates hepcidin via classical activin type II receptors ACVR2A and ACVR2B, noncanonical BMP type I receptors activin receptor-like kinase 2 and activin receptor-like kinase 3, and SMAD5. The coreceptor hemojuvelin binds to activin B and facilitates activin B-SMAD1/5/8 signaling. Activin B-SMAD1/5/8 signaling has some selectivity for hepatocyte-derived cells and is not enabled by hemojuvelin in other cell types. Liver activin B mRNA expression is up-regulated in multiple mouse models of inflammation associated with increased hepcidin and hypoferremia, including lipopolysaccharide, turpentine, and heat-killed Brucella abortus models. Finally, the activin inhibitor follistatin-315 blunts hepcidin induction by lipopolysaccharide or B. abortus in mice. Our data elucidate a novel mechanism for noncanonical SMAD activation and support a likely functional role for activin B in hepcidin stimulation during inflammation in vivo.
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Affiliation(s)
- Susanna Canali
- Program in Anemia Signaling Research (S.C., A.B.C., K.B.Z.-B., M.M., C.-Y.W., J.L.B.), Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114; Center for Hemochromatosis (S.C., A.P.), University Hospital of Modena and Reggio Emilia, Modena Italy 41124; and Department of Veterinary and Animal Science (A.S.), University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Amanda B Core
- Program in Anemia Signaling Research (S.C., A.B.C., K.B.Z.-B., M.M., C.-Y.W., J.L.B.), Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114; Center for Hemochromatosis (S.C., A.P.), University Hospital of Modena and Reggio Emilia, Modena Italy 41124; and Department of Veterinary and Animal Science (A.S.), University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Kimberly B Zumbrennen-Bullough
- Program in Anemia Signaling Research (S.C., A.B.C., K.B.Z.-B., M.M., C.-Y.W., J.L.B.), Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114; Center for Hemochromatosis (S.C., A.P.), University Hospital of Modena and Reggio Emilia, Modena Italy 41124; and Department of Veterinary and Animal Science (A.S.), University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Maria Merkulova
- Program in Anemia Signaling Research (S.C., A.B.C., K.B.Z.-B., M.M., C.-Y.W., J.L.B.), Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114; Center for Hemochromatosis (S.C., A.P.), University Hospital of Modena and Reggio Emilia, Modena Italy 41124; and Department of Veterinary and Animal Science (A.S.), University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Chia-Yu Wang
- Program in Anemia Signaling Research (S.C., A.B.C., K.B.Z.-B., M.M., C.-Y.W., J.L.B.), Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114; Center for Hemochromatosis (S.C., A.P.), University Hospital of Modena and Reggio Emilia, Modena Italy 41124; and Department of Veterinary and Animal Science (A.S.), University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Alan L Schneyer
- Program in Anemia Signaling Research (S.C., A.B.C., K.B.Z.-B., M.M., C.-Y.W., J.L.B.), Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114; Center for Hemochromatosis (S.C., A.P.), University Hospital of Modena and Reggio Emilia, Modena Italy 41124; and Department of Veterinary and Animal Science (A.S.), University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Antonello Pietrangelo
- Program in Anemia Signaling Research (S.C., A.B.C., K.B.Z.-B., M.M., C.-Y.W., J.L.B.), Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114; Center for Hemochromatosis (S.C., A.P.), University Hospital of Modena and Reggio Emilia, Modena Italy 41124; and Department of Veterinary and Animal Science (A.S.), University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Jodie L Babitt
- Program in Anemia Signaling Research (S.C., A.B.C., K.B.Z.-B., M.M., C.-Y.W., J.L.B.), Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114; Center for Hemochromatosis (S.C., A.P.), University Hospital of Modena and Reggio Emilia, Modena Italy 41124; and Department of Veterinary and Animal Science (A.S.), University of Massachusetts Amherst, Amherst, Massachusetts 01003
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11
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Merkulova M, Păunescu TG, Azroyan A, Marshansky V, Breton S, Brown D. Mapping the H(+) (V)-ATPase interactome: identification of proteins involved in trafficking, folding, assembly and phosphorylation. Sci Rep 2015; 5:14827. [PMID: 26442671 PMCID: PMC4595830 DOI: 10.1038/srep14827] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 09/02/2015] [Indexed: 12/04/2022] Open
Abstract
V-ATPases (H+ ATPases) are multisubunit, ATP-dependent proton pumps that regulate pH homeostasis in virtually all eukaryotes. They are involved in key cell biological processes including vesicle trafficking, endosomal pH sensing, membrane fusion and intracellular signaling. They also have critical systemic roles in renal acid excretion and blood pH balance, male fertility, bone remodeling, synaptic transmission, olfaction and hearing. Furthermore, V-ATPase dysfunction either results in or aggravates various other diseases, but little is known about the complex protein interactions that regulate these varied V-ATPase functions. Therefore, we performed a proteomic analysis to identify V-ATPase associated proteins and construct a V-ATPase interactome. Our analysis using kidney tissue revealed V-ATPase-associated protein clusters involved in protein quality control, complex assembly and intracellular trafficking. ARHGEF7, DMXL1, EZR, NCOA7, OXR1, RPS6KA3, SNX27 and 9 subunits of the chaperonin containing TCP1 complex (CCT) were found to interact with V-ATPase for the first time in this study. Knockdown of two interacting proteins, DMXL1 and WDR7, inhibited V-ATPase-mediated intracellular vesicle acidification in a kidney cell line, providing validation for the utility of our interactome as a screen for functionally important novel V-ATPase-regulating proteins. Our data, therefore, provide new insights and directions for the analysis of V-ATPase cell biology and (patho)physiology.
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Affiliation(s)
- Maria Merkulova
- MGH Center for Systems Biology, Program in Membrane Biology &Division of Nephrology, Richard B. Simches Research Center, Massachusetts General Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Teodor G Păunescu
- MGH Center for Systems Biology, Program in Membrane Biology &Division of Nephrology, Richard B. Simches Research Center, Massachusetts General Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Anie Azroyan
- MGH Center for Systems Biology, Program in Membrane Biology &Division of Nephrology, Richard B. Simches Research Center, Massachusetts General Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Vladimir Marshansky
- MGH Center for Systems Biology, Program in Membrane Biology &Division of Nephrology, Richard B. Simches Research Center, Massachusetts General Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Sylvie Breton
- MGH Center for Systems Biology, Program in Membrane Biology &Division of Nephrology, Richard B. Simches Research Center, Massachusetts General Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Dennis Brown
- MGH Center for Systems Biology, Program in Membrane Biology &Division of Nephrology, Richard B. Simches Research Center, Massachusetts General Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
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12
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Hosokawa H, Dip PV, Merkulova M, Bakulina A, Zhuang Z, Khatri A, Jian X, Randazzo PA, Ausiello DA, Grüber G, Marshansky V. V‐ATPase is a novel evolutionarily conserved cytohesin‐signaling receptor. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1031.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Phat V. Dip
- School Biol. Sci.Nanyang Tech.Univ.SingaporeSingapore
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Merkulova M, Hosokawa H, Bakulina A, Dip PV, Thaker YR, Khatri A, Ausiello DA, Grüber G, Marshansky V. Structural model of a2‐subunit N‐terminus and its binding interface for cytohesin‐2: Implication for regulation of V‐ATPase function. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1001.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Phat V. Dip
- School Biol. SciencesNanyang Technol. Univ.SingaporeSingapore
| | - Youg R. Thaker
- School Biol. SciencesNanyang Technol. Univ.SingaporeSingapore
| | | | | | - Gerhard Grüber
- School Biol. SciencesNanyang Technol. Univ.SingaporeSingapore
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Hosokawa H, Dip PV, Merkulova M, Bakulina A, Zhuang Z, Khatri A, Jian X, Keating SM, Bueler SA, Rubinstein JL, Randazzo PA, Ausiello DA, Grüber G, Marshansky V. The N termini of a-subunit isoforms are involved in signaling between vacuolar H+-ATPase (V-ATPase) and cytohesin-2. J Biol Chem 2013; 288:5896-913. [PMID: 23288846 DOI: 10.1074/jbc.m112.409169] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previously, we reported an acidification-dependent interaction of the endosomal vacuolar H(+)-ATPase (V-ATPase) with cytohesin-2, a GDP/GTP exchange factor (GEF), suggesting that it functions as a pH-sensing receptor. Here, we have studied the molecular mechanism of signaling between the V-ATPase, cytohesin-2, and Arf GTP-binding proteins. We found that part of the N-terminal cytosolic tail of the V-ATPase a2-subunit (a2N), corresponding to its first 17 amino acids (a2N(1-17)), potently modulates the enzymatic GDP/GTP exchange activity of cytohesin-2. Moreover, this peptide strongly inhibits GEF activity via direct interaction with the Sec7 domain of cytohesin-2. The structure of a2N(1-17) and its amino acids Phe(5), Met(10), and Gln(14) involved in interaction with Sec7 domain were determined by NMR spectroscopy analysis. In silico docking experiments revealed that part of the V-ATPase formed by its a2N(1-17) epitope competes with the switch 2 region of Arf1 and Arf6 for binding to the Sec7 domain of cytohesin-2. The amino acid sequence alignment and GEF activity studies also uncovered the conserved character of signaling between all four (a1-a4) a-subunit isoforms of mammalian V-ATPase and cytohesin-2. Moreover, the conserved character of this phenomenon was also confirmed in experiments showing binding of mammalian cytohesin-2 to the intact yeast V-ATPase holo-complex. Thus, here we have uncovered an evolutionarily conserved function of the V-ATPase as a novel cytohesin-signaling receptor.
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Affiliation(s)
- Hiroyuki Hosokawa
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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Merkulova M, Hurtado-Lorenzo A, Hosokawa H, Zhuang Z, Brown D, Ausiello DA, Marshansky V. Aldolase directly interacts with ARNO and modulates cell morphology and acidic vesicle distribution. Am J Physiol Cell Physiol 2011; 300:C1442-55. [PMID: 21307348 DOI: 10.1152/ajpcell.00076.2010] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Previously, we demonstrated that the vacuolar-type H(+)-ATPase (V-ATPase) a2-subunit functions as an endosomal pH sensor that interacts with the ADP-ribosylation factor (Arf) guanine nucleotide exchange factor, ARNO. In the present study, we showed that ARNO directly interacts not only with the a2-subunit but with all a-isoforms (a1-a4) of the V-ATPase, indicating a widespread regulatory interaction between V-ATPase and Arf GTPases. We then extended our search for other ARNO effectors that may modulate V-ATPase-dependent vesicular trafficking events and actin cytoskeleton remodeling. Pull-down experiments using cytosol of mouse proximal tubule cells (MTCs) showed that ARNO interacts with aldolase, but not with other enzymes of the glycolytic pathway. Direct interaction of aldolase with the pleckstrin homology domain of ARNO was revealed by pull-down assays using recombinant proteins, and surface plasmon resonance revealed their high avidity interaction with a dissociation constant: K(D) = 2.84 × 10(-10) M. MTC cell fractionation revealed that aldolase is also associated with membranes of early endosomes. Functionally, aldolase knockdown in HeLa cells produced striking morphological changes accompanied by long filamentous cell protrusions and acidic vesicle redistribution. However, the 50% knockdown we achieved did not modulate the acidification capacity of endosomal/lysosomal compartments. Finally, a combination of small interfering RNA knockdown and overexpression revealed that the expression of aldolase is inversely correlated with gelsolin levels in HeLa cells. In summary, we have shown that aldolase forms a complex with ARNO/Arf6 and the V-ATPase and that it may contribute to remodeling of the actin cytoskeleton and/or the trafficking and redistribution of V-ATPase-dependent acidic compartments via a combination of protein-protein interaction and gene expression mechanisms.
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Affiliation(s)
- Maria Merkulova
- Program in Membrane Biology and Nephrology Division, Center for Systems Biology, Simches Research Center, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA
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Merkulova M, McKee M, Dip PV, Grüber G, Marshansky V. N-terminal domain of the V-ATPase a2-subunit displays integral membrane protein properties. Protein Sci 2011; 19:1850-62. [PMID: 20669186 DOI: 10.1002/pro.470] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
V-ATPase is a multisubunit membrane complex that functions as nanomotor coupling ATP hydrolysis with proton translocation across biological membranes. Recently, we uncovered details of the mechanism of interaction between the N-terminal tail of the V-ATPase a2-subunit isoform (a2N(1-402)) and ARNO, a GTP/GDP exchange factor for Arf-family small GTPases. Here, we describe the development of two methods for preparation of the a2N(1-402) recombinant protein in milligram quantities sufficient for further biochemical, biophysical, and structural studies. We found two alternative amphiphilic chemicals that were required for protein stability and solubility during purification: (i) non-detergent sulfobetaine NDSB-256 and (ii) zwitterionic detergent FOS-CHOLINE®12 (FC-12). Moreover, the other factors including mild alkaline pH, the presence of reducing agents and the absence of salt were beneficial for stabilization and solubilization of the protein. A preparation of a2N(1-402) in NDSB-256 was successfully used in pull-down and BIAcore™ protein-protein interaction experiments with ARNO, whereas the purity and quality of the second preparation in FC-12 was validated by size-exclusion chromatography and CD spectroscopy. Surprisingly, the detergent requirement for stabilization and solubilization of a2N(1-402) and its cosedimentation with liposomes were different from peripheral domains of other transmembrane proteins. Thus, our data suggest that in contrast to current models, so called "cytosolic" tail of the a2-subunit might actually be embedded into and/or closely associated with membrane phospholipids even in the absence of any obvious predicted transmembrane segments. We propose that a2N(1-402) should be categorized as an integral monotopic domain of the a2-subunit isoform of the V-ATPase.
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Affiliation(s)
- Maria Merkulova
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Simches Research Center, Massachusetts General Hospital and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02114, USA
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Merkulova M, Bakulina A, Thaker YR, Grüber G, Marshansky V. Specific motifs of the V-ATPase a2-subunit isoform interact with catalytic and regulatory domains of ARNO. Biochim Biophys Acta 2010; 1797:1398-409. [PMID: 20153292 DOI: 10.1016/j.bbabio.2010.02.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 01/11/2010] [Accepted: 02/08/2010] [Indexed: 11/19/2022]
Abstract
We have previously shown that the V-ATPase a2-subunit isoform interacts specifically, and in an intra-endosomal acidification-dependent manner, with the Arf-GEF ARNO. In the present study, we examined the molecular mechanism of this interaction using synthetic peptides and purified recombinant proteins in protein-association assays. In these experiments, we revealed the involvement of multiple sites on the N-terminus of the V-ATPase a2-subunit (a2N) in the association with ARNO. While six a2N-derived peptides interact with wild-type ARNO, only two of them (named a2N-01 and a2N-03) bind to its catalytic Sec7-domain. However, of these, only the a2N-01 peptide (MGSLFRSESMCLAQLFL) showed specificity towards the Sec7-domain compared to other domains of the ARNO protein. Surface plasmon resonance kinetic analysis revealed a very strong binding affinity between this a2N-01 peptide and the Sec7-domain of ARNO, with dissociation constant KD=3.44x10(-7) M, similar to the KD=3.13x10(-7) M binding affinity between wild-type a2N and the full-length ARNO protein. In further pull-down experiments, we also revealed the involvement of multiple sites on ARNO itself in the association with a2N. However, while its catalytic Sec7-domain has the strongest interaction, the PH-, and PB-domains show much weaker binding to a2N. Interestingly, an interaction of the a2N to a peptide corresponding to ARNO's PB-domain was abolished by phosphorylation of ARNO residue Ser392. The 3D-structures of the non-phosphorylated and phosphorylated peptides were resolved by NMR spectroscopy, and we have identified rearrangements resulting from Ser392 phosphorylation. Homology modeling suggests that these alterations may modulate the access of the a2N to its interaction pocket on ARNO that is formed by the Sec7 and PB-domains. Overall, our data indicate that the interaction between the a2-subunit of V-ATPase and ARNO is a complex process involving various binding sites on both proteins. Importantly, the binding affinity between the a2-subunit and ARNO is in the same range as those previously reported for the intramolecular association of subunits within V-ATPase complex itself, indicating an important cell biological role for the interaction between the V-ATPase and small GTPase regulatory proteins.
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Affiliation(s)
- Maria Merkulova
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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Merkulova M, Hurtado‐Lorenzo A, Brown D, Ausiello D, Marshansky V. V‐ATPase/small GTPase/aldolase complex and regulation of endosomal/lysosomal protein degradative pathway. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.877.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Maria Merkulova
- Program in Membrane BiologyCenter for Systems BiologySimches Research CenterMassachusetts General HospitalBostonMA
| | - Andres Hurtado‐Lorenzo
- Program in Membrane BiologyCenter for Systems BiologySimches Research CenterMassachusetts General HospitalBostonMA
| | - Dennis Brown
- Program in Membrane BiologyCenter for Systems BiologySimches Research CenterMassachusetts General HospitalBostonMA
| | - Dennis Ausiello
- Program in Membrane BiologyCenter for Systems BiologySimches Research CenterMassachusetts General HospitalBostonMA
| | - Vladimir Marshansky
- Program in Membrane BiologyCenter for Systems BiologySimches Research CenterMassachusetts General HospitalBostonMA
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Merkulova M, Marshansky V. Function of V‐ATPase as a putative endosomal pH‐senor: mapping the interaction sites between V‐ATPase a2‐isoform and ARNO. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1156.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Maria Merkulova
- Program in Membrane BiologyCenter for System BiologySimches Research CenterMassachusetts General HospitalHarvard Medical SchoolBostonMA
| | - Vladimir Marshansky
- Program in Membrane BiologyCenter for System BiologySimches Research CenterMassachusetts General HospitalHarvard Medical SchoolBostonMA
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Bankaitis VA, Vincent P, Merkulova M, Tyeryar K, Liu Y. Phosphatidylinositol transfer proteins and functional specification of lipid signaling pools. ACTA ACUST UNITED AC 2007; 47:27-40. [PMID: 17335879 PMCID: PMC2080876 DOI: 10.1016/j.advenzreg.2006.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Vytas A Bankaitis
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA.
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Abstract
Protein-lipid interactions are important for protein targeting, signal transduction, lipid transport, and the maintenance of cellular compartments and membranes. Specific lipid-binding protein domains, such as PH, FYVE, PX, PHD, C2 and SEC14 homology domains, mediate interactions between proteins and specific phospholipids. We recently cloned a 45-kDa protein from rat olfactory epithelium, which is homologous to the yeast Sec14p phosphatidylinositol (PtdIns) transfer protein and we report here that this protein binds to PtdIns(3,4,5)P3 and far weaker to less phosphorylated derivatives of PtdIns. Expression of the p45 protein in COS-1 cells resulted in accumulation of the protein in secretory vesicles and in the extracellular space. The secreted material contained PtdIns(3,4,5)P3. Our findings are the first report of a Sec14p-like protein involved in transport out of a cell and, to the best of our knowledge, inositol-containing phospholipids have not previously been detected in the extracellular space. Our findings suggest that p45 and phosphoinositides may participate in the formation of the protective mucus on nasal epithelium.
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Affiliation(s)
- Maria Merkulova
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
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