1
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He X, Lin Z, Ning J, Li N, Cui X, Zhao B, Hong F, Miao J. Promoting TTC4 and HSP70 interaction and translocation of annexin A7 to lysosome inhibits apoptosis in vascular endothelial cells. FASEB J 2020; 34:12932-12945. [PMID: 33000523 DOI: 10.1096/fj.202000067r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 07/12/2020] [Accepted: 07/21/2020] [Indexed: 01/16/2023]
Abstract
We previously demonstrated that Tetraticopeptide 4 (TTC4) inhibited apoptosis in vascular endothelial cells (VEC) deprived of serum and fibroblast growth factor 2 (FGF-2). In this study, we aimed to resolve the mechanism of TTC4 inhibiting VEC apoptosis. TTC4, predicted as a HSP70 co-chaperone protein, may regulate the fate of cells by affecting the activity of HSP70, however, there is no experimental evidence showing the interaction of TTC4 and HSP70. Using Co-immunoprecipitation (Co-IP), we demonstrated that TTC4 interacted with HSP70. If HSP70 was knockdown, TTC4 no longer suppressed apoptosis. Furthermore, we found ABO, an inhibitor of annexin A7 (ANXA7) GTPase, could promote the interaction of TTC4 and HSP70 and the translocation of ANXA7 to lysosome. At the same time, ABO inhibited the interaction of HSP70 and ANXA7. Moreover, Akt, as a downstream effector of HSP70 was upregulated, and ANXA7 translocating to lysosome protected the stability of lysosomal membrane. Here, we discovered a special mechanism by which TTC4 inhibited apoptosis via HSP70 in VECs. On the one hand, increasing TTC4 and HSP70 interaction upregulated Akt that inhibited apoptosis. On the other hand, decreasing HSP70 and ANXA7 interaction promoted the translocation of ANXA7 to lysosome, which inhibited apoptosis through protecting the lysosomal membrane stability.
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Affiliation(s)
- Xiaoying He
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Qingdao, P.R. China
| | - Zhaomin Lin
- Institute of Medical Science, The Second Hospital of Shandong University, Jinan, P.R. China
| | - Junya Ning
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Qingdao, P.R. China
| | - Na Li
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Qingdao, P.R. China
| | - Xiaoling Cui
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Qingdao, P.R. China
| | - Baoxiang Zhao
- Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan, P.R. China
| | - Fanzhen Hong
- Department of Obstetrics, The Second Hospital of Shandong University, Jinan, P.R. China
| | - Junying Miao
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Qingdao, P.R. China.,The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Shandong University Qilu Hospital, Jinan, P.R. China
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2
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Korolkova OY, Widatalla SE, Williams SD, Whalen DS, Beasley HK, Ochieng J, Grewal T, Sakwe AM. Diverse Roles of Annexin A6 in Triple-Negative Breast Cancer Diagnosis, Prognosis and EGFR-Targeted Therapies. Cells 2020; 9:E1855. [PMID: 32784650 PMCID: PMC7465958 DOI: 10.3390/cells9081855] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 12/20/2022] Open
Abstract
The calcium (Ca2+)-dependent membrane-binding Annexin A6 (AnxA6), is a multifunctional, predominantly intracellular scaffolding protein, now known to play relevant roles in different cancer types through diverse, often cell-type-specific mechanisms. AnxA6 is differentially expressed in various stages/subtypes of several cancers, and its expression in certain tumor cells is also induced by a variety of pharmacological drugs. Together with the secretion of AnxA6 as a component of extracellular vesicles, this suggests that AnxA6 mediates distinct tumor progression patterns via extracellular and/or intracellular activities. Although it lacks enzymatic activity, some of the AnxA6-mediated functions involving membrane, nucleotide and cholesterol binding as well as the scaffolding of specific proteins or multifactorial protein complexes, suggest its potential utility in the diagnosis, prognosis and therapeutic strategies for various cancers. In breast cancer, the low AnxA6 expression levels in the more aggressive basal-like triple-negative breast cancer (TNBC) subtype correlate with its tumor suppressor activity and the poor overall survival of basal-like TNBC patients. In this review, we highlight the potential tumor suppressor function of AnxA6 in TNBC progression and metastasis, the relevance of AnxA6 in the diagnosis and prognosis of several cancers and discuss the concept of therapy-induced expression of AnxA6 as a novel mechanism for acquired resistance of TNBC to tyrosine kinase inhibitors.
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Affiliation(s)
- Olga Y. Korolkova
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Sarrah E. Widatalla
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Stephen D. Williams
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Diva S. Whalen
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Heather K. Beasley
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Josiah Ochieng
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
| | - Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia;
| | - Amos M. Sakwe
- Department of Biochemistry and Cancer Biology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN 37208, USA; (O.Y.K.); (S.E.W.); (S.D.W.); (D.S.W.); (H.K.B.); (J.O.)
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3
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Rentero C, Blanco-Muñoz P, Meneses-Salas E, Grewal T, Enrich C. Annexins-Coordinators of Cholesterol Homeostasis in Endocytic Pathways. Int J Mol Sci 2018; 19:E1444. [PMID: 29757220 PMCID: PMC5983649 DOI: 10.3390/ijms19051444] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/09/2018] [Accepted: 05/10/2018] [Indexed: 02/07/2023] Open
Abstract
The spatiotemporal regulation of calcium (Ca2+) storage in late endosomes (LE) and lysosomes (Lys) is increasingly recognized to influence a variety of membrane trafficking events, including endocytosis, exocytosis, and autophagy. Alterations in Ca2+ homeostasis within the LE/Lys compartment are implicated in human diseases, ranging from lysosomal storage diseases (LSDs) to neurodegeneration and cancer, and they correlate with changes in the membrane binding behaviour of Ca2+-binding proteins. This also includes Annexins (AnxA), which is a family of Ca2+-binding proteins participating in membrane traffic and tethering, microdomain organization, cytoskeleton interactions, Ca2+ signalling, and LE/Lys positioning. Although our knowledge regarding the way Annexins contribute to LE/Lys functions is still incomplete, recruitment of Annexins to LE/Lys is greatly influenced by the availability of Annexin bindings sites, including acidic phospholipids, such as phosphatidylserine (PS) and phosphatidic acid (PA), cholesterol, and phosphatidylinositol (4,5)-bisphosphate (PIP2). Moreover, the cytosolic portion of LE/Lys membrane proteins may also, directly or indirectly, determine the recruitment of Annexins to LE. Strikingly, within LE/Lys, AnxA1, A2, A6, and A8 differentially contribute to cholesterol transport along the endocytic route, in particular, cholesterol transfer between LE and other compartments, positioning Annexins at the centre of major pathways mediating cellular cholesterol homeostasis. Underlying mechanisms include the formation of membrane contact sites (MCS) and intraluminal vesicles (ILV), as well as the modulation of LE-cholesterol transporter activity. In this review, we will summarize the current understanding how Annexins contribute to influence LE/Lys membrane transport and associated functions.
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Affiliation(s)
- Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona. 08036 Barcelona. Spain.
| | - Patricia Blanco-Muñoz
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona. 08036 Barcelona. Spain.
| | - Elsa Meneses-Salas
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona. 08036 Barcelona. Spain.
| | - Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia.
| | - Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona. 08036 Barcelona. Spain.
- Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain.
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Enrich C, Rentero C, Meneses-Salas E, Tebar F, Grewal T. Annexins: Ca 2+ Effectors Determining Membrane Trafficking in the Late Endocytic Compartment. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 981:351-385. [PMID: 29594868 DOI: 10.1007/978-3-319-55858-5_14] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Despite the discovery of annexins 40 years ago, we are just beginning to understand some of the functions of these still enigmatic proteins. Defined and characterized by their ability to bind anionic membrane lipids in a Ca2+-dependent manner, each annexin has to be considered a multifunctional protein, with a multitude of cellular locations and diverse activities. Underlying causes for this considerable functional diversity include their capability to associate with multiple cytosolic and membrane proteins. In recent years, the increasingly recognized establishment of membrane contact sites between subcellular compartments opens a new scenario for annexins as instrumental players to link Ca2+ signalling with the integration of membrane trafficking in many facets of cell physiology. In this chapter, we review and discuss current knowledge on the contribution of annexins in the biogenesis and functioning of the late endocytic compartment, affecting endo- and exocytic pathways in a variety of physiological consequences ranging from membrane repair, lysosomal exocytosis, to cell migration.
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Affiliation(s)
- Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica (CELLEX), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. .,Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain.
| | - Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica (CELLEX), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Elsa Meneses-Salas
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica (CELLEX), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Francesc Tebar
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica (CELLEX), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, Australia
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Groves P, Strzelecka-Kiliszek A, Sekrecka-Belniak A, Canales A, Jiménez-Barbero J, Bandorowicz-Pikula J, Pikula S, Cañada FJ. Exploring NMR methods as a tool to select suitable fluorescent nucleotide analogues. Org Biomol Chem 2014; 11:5332-8. [PMID: 23842795 DOI: 10.1039/c3ob40159f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Fluorescent analogues provide important tools for biochemical/biophysical research. However, the analogues contain chemical modifications much larger than those known to affect ligand-binding, such as the inversion of a carbon centre or substitution of an atom. We lack experimental tools and protocols to select the most appropriate fluorescent analogue. Herein, we use several NMR spectroscopy methods, including Saturation Transfer Difference (STD), STD competition and transferred nuclear Overhauser effect spectroscopy (Tr-NOESY), as tools to select appropriate fluorescent probes. Annexin A6 (AnxA6) is a ubiquitous protein that forms in vitro GTP-induced ion channels. We used this protein as a model and screened guanosine triphosphate (GTP) and four fluorescent analogues against AnxA6. STD reported that the GTP moiety of all ligands made similar contacts with the protein, despite additional interactions between the fluorescent tags and AnxA6. Competition STD experiments verified that the analogues and GTP bind to the same site. Tr-NOESY indicated that the bound conformation of the base relative to ribose is altered for some analogues compared to GTP. MANT-GTP or the BODIPY thioester of guanosine 5'-O-(3-thiotriphosphate) are the most suitable fluorescent analogues for AnxA6, according to NMR. These results reveal NMR as a useful technique to select and design proper fluorescent tags for biochemical/biophysical assays.
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Affiliation(s)
- Patrick Groves
- Chemical Biology Division, Instituto de Tecnologia Química e Biológica (ITQB-UNL), Oeiras, Portugal.
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6
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Domon MM, Nasir MN, Pikula S, Besson F. Influence of the 524-VAAEIL-529 sequence of annexins A6 in their interfacial behavior and interaction with lipid monolayers. J Colloid Interface Sci 2013; 403:99-104. [DOI: 10.1016/j.jcis.2013.04.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 04/18/2013] [Accepted: 04/19/2013] [Indexed: 10/26/2022]
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7
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Domon MM, Besson F, Tylki-Szymanska A, Bandorowicz-Pikula J, Pikula S. Interaction of AnxA6 with isolated and artificial lipid microdomains; importance of lipid composition and calcium content. MOLECULAR BIOSYSTEMS 2013; 9:668-76. [DOI: 10.1039/c3mb25487a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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8
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Abstract
Annexins are multifunctional lipid-binding proteins. Plant annexins are expressed throughout the life cycle and are under environmental control. Their association or insertion into membranes may be governed by a range of local conditions (Ca(2+), pH, voltage or lipid identity) and nonclassical sorting motifs. Protein functions include exocytosis, actin binding, peroxidase activity, callose synthase regulation and ion transport. As such, annexins appear capable of linking Ca(2+), redox and lipid signalling to coordinate development with responses to the biotic and abiotic environment. Significant advances in plant annexin research have been made in the past 2 yr. Here, we review the basis of annexin multifunctionality and suggest how these proteins may operate in the life and death of a plant cell.
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Bandorowicz-Pikula J, Buchet R, Cañada FJ, Clémancey M, Groves P, Jiménez-Barbero J, Lancelin JM, Marcillat O, Pikula S, Sekrecka-Belniak A, Strzelecka-Kiliszek A. Characterization of caged compounds binding to proteins by NMR spectroscopy. Biochem Biophys Res Commun 2010; 400:447-51. [PMID: 20804737 DOI: 10.1016/j.bbrc.2010.08.104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 08/25/2010] [Indexed: 10/19/2022]
Abstract
Photolysable caged ligands are used to investigate protein function and activity. Here, we investigate the binding properties of caged nucleotides and their photo released products to well established but evolutionary and structurally unrelated nucleotide-binding proteins, rabbit muscle creatine kinase (RMCK) and human annexin A6 (hAnxA6), using saturation transfer difference NMR spectroscopy. We detect the binding of the caged nucleotides and discuss the general implications on interpreting data collected with photolysable caged ligands using different techniques. Strategies to avoid non-specific binding of caged compound to certain proteins are also suggested.
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Affiliation(s)
- Joanna Bandorowicz-Pikula
- Department of Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02093 Warsaw, Poland
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Interaction of annexin A6 with cholesterol rich membranes is pH-dependent and mediated by the sterol OH. J Colloid Interface Sci 2010; 346:436-41. [DOI: 10.1016/j.jcis.2010.03.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 03/08/2010] [Accepted: 03/09/2010] [Indexed: 11/17/2022]
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11
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Singh NR, Rondeau P, Hoareau L, Bourdon E. Identification of preferential protein targets for carbonylation in human mature adipocytes treated with native or glycated albumin. Free Radic Res 2009; 41:1078-88. [PMID: 17886029 DOI: 10.1080/10715760701487674] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Oxidative modifications in proteins can participate in the regulation of cellular functions and are frequently observed in numerous states of diseases. Albumin can undergo increased glycation during diabetes. An accumulation of oxidatively modified proteins in human mature adipocytes incubated with glycated albumin has previously been described. This study herein reports the identification of specifically carbonylated targets following separation of the cell proteins by 2D gels, Western blotting and mass spectrometry analyses. It identified eight oxidatively modified proteins, two of which (ACTB and Annexin A2) appeared as significantly more carbonylated in adipocytes treated with glycated albumin than with native albumin. Intracellular stress, evaluated in SW872 cell line, showed an impairment in the protective antioxidant action exerted by native BSA after the glycation of the protein. Decreased proteasome peptidase activities were found in glycated BSA-treated mature adipocytes. The data suggest an association of oxidative damage with the progression of diabetes disorders at the adipocytes level.
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Affiliation(s)
- Nihar Ranjan Singh
- Laboratoire de Biochimie et Génétique Moléculaire, Université de La Réunion, Cedex 09, Saint Denis, France
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12
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Strzelecka-Kiliszek A, Buszewska ME, Podszywalow-Bartnicka P, Pikula S, Otulak K, Buchet R, Bandorowicz-Pikula J. Calcium- and pH-dependent localization of annexin A6 isoforms in Balb/3T3 fibroblasts reflecting their potential participation in vesicular transport. J Cell Biochem 2008; 104:418-34. [PMID: 18044716 DOI: 10.1002/jcb.21632] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Annexin A6 (AnxA6), calcium- and membrane-binding protein, is involved in membrane dynamics. It exists in the cell in two isoforms, AnxA6-1 and AnxA6-2, varying only by the VAAEIL sequence. In most cells, AnxA6-1 predominates. A limited number of observations suggests that both isoforms differ from each other functionally. The EGF-dependent Ca(2+) influx in A431 cells is inhibited only by AnxA6-1. Moreover, AnxA6-2 was found to exhibit higher affinity for Ca(2+). In this report we addressed the potential significance of the VAAEIL deletion in AnxA6-2. For this purpose, we expressed AnxA6 isoform cDNAs in bacteria or mouse Balb/3T3 fibroblasts. The recombinant AnxA6-2 was characterized by a less extended molecular shape than that of AnxA6-1 and required a narrower [Ca(2+)] range to bind liposomes. Upon lowering pH in the presence of EGTA recombinant AnxA6-2 became less hydrophobic than AnxA6-1 as revealed by the Triton X-114 partition. Furthermore, AnxA6-2 revealed stronger F-actin binding than that of AnxA6-1. Immunofluorescence microscopy showed that the EGFP-tagged AnxA6 isoforms expressed in Balb/3T3 fibroblasts relocate in a Ca(2+)- and H(+)-sensitive manner to the vesicular structures in a perinuclear region or in cytosol. Cell fractionation showed that in resting conditions AnxA6-1 is associated with early endosomes and AnxA6-2 with late endosomes, and an increase in [Ca(2+)] and/or [H(+)] induced their opposite distribution. These findings suggest a potentially independent regulation, localization, and function of AnxA6 isoforms in Balb/3T3 fibroblasts. More generally, our findings suggest distinct functions of AnxA6 isoforms in membrane dynamics.
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Moran N. Osmoregulation of leaf motor cells. FEBS Lett 2007; 581:2337-47. [PMID: 17434488 DOI: 10.1016/j.febslet.2007.04.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2007] [Revised: 03/31/2007] [Accepted: 04/02/2007] [Indexed: 11/18/2022]
Abstract
"Osmotic Motors"--the best-documented explanation for plant leaf movements--frequently reside in specialized motor leaf organs, pulvini. The movements result from dissimilar volume and turgor changes in two oppositely positioned parts of the pulvinus. This Osmotic Motor is powered by a plasma membrane proton ATPase, which drives KCl fluxes and, consequently, water, across the pulvinus into swelling cells and out of shrinking cells. Light signals and signals from the endogenous biological clock converge on the channels through which these fluxes occur. These channels and their regulatory pathways in the pulvinus are the topic of this review.
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Affiliation(s)
- Nava Moran
- The R.H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
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14
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Balcerzak M, Bandorowicz-Pikula J, Buchet R, Pikula S. A novel retinoid binding property of human annexin A6. FEBS Lett 2006; 580:3065-9. [PMID: 16674946 DOI: 10.1016/j.febslet.2006.04.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 04/18/2006] [Accepted: 04/19/2006] [Indexed: 10/24/2022]
Abstract
Vitamin A (all-trans retinol) and all-trans retinoid acid (ATRA) interacted with human annexin A6 (AnxA6) as evidenced by AnxA6-induced blue shift of retinoid absorption maxima, by AnxA6-Trp fluorescence quenching and by a fluorescence resonance energy transfer from a Trp residue of AnxA6 to retinol. In addition, both retinoids stimulated the calcium-dependent binding of AnxA6 to liposomes, accompanied by oligomerization of AnxA6. Up to our knowledge, it is a first report supporting the hypothesis of a direct implication of AnxA6 in vitamin A-dependent tissue mineralization.
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Affiliation(s)
- Marcin Balcerzak
- Department of Cellular Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093 Warsaw, Poland
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