1
|
Cao J, Wan S, Chen S, Yang L. ANXA6: a key molecular player in cancer progression and drug resistance. Discov Oncol 2023; 14:53. [PMID: 37129645 PMCID: PMC10154440 DOI: 10.1007/s12672-023-00662-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/17/2023] [Indexed: 05/03/2023] Open
Abstract
Annexin-A6 (ANXA6), a Ca2+-dependent membrane binding protein, is the largest of all conserved annexin families and highly expressed in the plasma membrane and endosomal compartments. As a multifunctional scaffold protein, ANXA6 can interact with phospholipid membranes and various signaling proteins. These properties enable ANXA6 to participate in signal transduction, cholesterol homeostasis, intracellular/extracellular membrane transport, and repair of membrane domains, etc. Many studies have demonstrated that the expression of ANXA6 is consistently altered during tumor formation and progression. ANXA6 is currently known to mediate different patterns of tumor progression in different cancer types through multiple cancer-type specific mechanisms. ANXA6 is a potentially valuable marker in the diagnosis, progression, and treatment strategy of various cancers. This review mainly summarizes recent findings on the mechanism of tumor formation, development, and drug resistance of ANXA6. The contents reviewed herein may expand researchers' understanding of ANXA6 and contribute to developing ANXA6-based diagnostic and therapeutic strategies.
Collapse
Affiliation(s)
- Jinlong Cao
- Department of Urology, Lanzhou University Second Hospital, Lanzhou, 730000, China
- Gansu Province Clinical Research Center for Urology, Lanzhou, 730000, China
| | - Shun Wan
- Department of Urology, Lanzhou University Second Hospital, Lanzhou, 730000, China
- Gansu Province Clinical Research Center for Urology, Lanzhou, 730000, China
| | - Siyu Chen
- Department of Urology, Lanzhou University Second Hospital, Lanzhou, 730000, China
- Gansu Province Clinical Research Center for Urology, Lanzhou, 730000, China
| | - Li Yang
- Department of Urology, Lanzhou University Second Hospital, Lanzhou, 730000, China.
- Gansu Province Clinical Research Center for Urology, Lanzhou, 730000, China.
| |
Collapse
|
2
|
Grewal T, Hoque M, Conway JRW, Reverter M, Wahba M, Beevi SS, Timpson P, Enrich C, Rentero C. Annexin A6-A multifunctional scaffold in cell motility. Cell Adh Migr 2017; 11:288-304. [PMID: 28060548 DOI: 10.1080/19336918.2016.1268318] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Annexin A6 (AnxA6) belongs to a highly conserved protein family characterized by their calcium (Ca2+)-dependent binding to phospholipids. Over the years, immunohistochemistry, subcellular fractionations, and live cell microscopy established that AnxA6 is predominantly found at the plasma membrane and endosomal compartments. In these locations, AnxA6 acts as a multifunctional scaffold protein, recruiting signaling proteins, modulating cholesterol and membrane transport and influencing actin dynamics. These activities enable AnxA6 to contribute to the formation of multifactorial protein complexes and membrane domains relevant in signal transduction, cholesterol homeostasis and endo-/exocytic membrane transport. Hence, AnxA6 has been implicated in many biological processes, including cell proliferation, survival, differentiation, inflammation, but also membrane repair and viral infection. More recently, we and others identified roles for AnxA6 in cancer cell migration and invasion. This review will discuss how the multiple scaffold functions may enable AnxA6 to modulate migratory cell behavior in health and disease.
Collapse
Affiliation(s)
- Thomas Grewal
- a Faculty of Pharmacy , University of Sydney , Sydney , NSW , Australia
| | - Monira Hoque
- a Faculty of Pharmacy , University of Sydney , Sydney , NSW , Australia
| | - James R W Conway
- b The Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, St Vincent's Clinical School, Faculty of Medicine , University of New South Wales , Sydney , NSW , Australia
| | - Meritxell Reverter
- c Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina , Universitat de Barcelona , Barcelona , Spain
| | - Mohamed Wahba
- a Faculty of Pharmacy , University of Sydney , Sydney , NSW , Australia
| | - Syed S Beevi
- a Faculty of Pharmacy , University of Sydney , Sydney , NSW , Australia
| | - Paul Timpson
- b The Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Division, St Vincent's Clinical School, Faculty of Medicine , University of New South Wales , Sydney , NSW , Australia
| | - Carlos Enrich
- c Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina , Universitat de Barcelona , Barcelona , Spain
| | - Carles Rentero
- c Departament de Biomedicina, Unitat de Biologia Cel·lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina , Universitat de Barcelona , Barcelona , Spain
| |
Collapse
|
3
|
Banerjee P, Bandyopadhyay A. Cytosolic dynamics of annexin A6 trigger feedback regulation of hypertrophy via atrial natriuretic peptide in cardiomyocytes. J Biol Chem 2014; 289:5371-85. [PMID: 24403064 DOI: 10.1074/jbc.m113.514810] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Malfunctions in regulatory pathways that control cell size are prominent in pathological cardiac hypertrophy. Here, we show annexin A6 (Anxa6) to be a crucial regulator of atrial natriuretic peptide (ANP)-mediated counterhypertrophic responses in cardiomyocytes. Adrenergic stimulation of H9c2 cardiomyocytes by phenylephrine (PE) increased the cell size with enhanced expression of biochemical markers of hypertrophy, concomitant with elevated expression and subcellular redistribution of Anxa6. Stable cell lines with controlled increase in Anxa6 levels were protected against PE-induced adverse changes, whereas Anxa6 knockdown augmented the hypertrophic responses. Strikingly, Anxa6 knockdown also abrogated PE-induced juxtanuclear accumulation of secretory granules (SG) containing ANP propeptides (pro-ANP), a signature of maladaptive hypertrophy having counteractive functions. Mechanistically, PE treatment prompted a dynamic association of Anxa6 with pro-ANP-SG, parallel to their participation in anterograde traffic, in an isoform-specific fashion. Moreover, Anxa6 mutants that failed to associate with pro-ANP hindered ANP-mediated protection against hypertrophy, which was rescued, at least partially, by WT Anxa6. Additionally, elevated intracellular calcium (Ca(2+)) stimulated Anxa6-pro-ANP colocalization and membrane association. It also rescued pro-ANP translocation in cells expressing an Anxa6 mutant (Anxa6(ΔC)). Furthermore, stable overexpression of Anxa6(T356D), a mutant with superior flexibility, provided enhanced protection against PE, compared with WT, presumably due to enhanced membrane-binding capacity. Together, the present study delivers a cooperative mechanism where Anxa6 potentiates ANP-dependent counterhypertrophic responses in cardiomyocytes by facilitating regulated traffic of pro-ANP.
Collapse
Affiliation(s)
- Priyam Banerjee
- From the Cell Biology and Physiology Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata-700 032, West Bengal, India
| | | |
Collapse
|
4
|
Tjäderhane L, Haapasalo M. The dentin-pulp border: a dynamic interface between hard and soft tissues. ACTA ACUST UNITED AC 2012. [DOI: 10.1111/j.1601-1546.2012.00266.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
5
|
Goldberg M, Kulkarni AB, Young M, Boskey A. Dentin: structure, composition and mineralization. Front Biosci (Elite Ed) 2011; 3:711-35. [PMID: 21196346 DOI: 10.2741/e281] [Citation(s) in RCA: 391] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We review firstly the specificities of the different types of dentin present in mammalian teeth. The outer layers include the mantle dentin, the Tomes' granular and the hyaline Hopewell-Smith's layers. Circumpulpal dentin forming the bulk of the tooth, comprises intertubular and peritubular dentin. In addition to physiological primary and secondary dentin formation, reactionary dentin is produced in response to pathological events. Secondly, we evaluate the role of odontoblasts in dentin formation, their implication in the synthesis and secretion of type I collagen fibrils and non-collagenous molecules. Thirdly, we study the composition and functions of dentin extracellular matrix (ECM) molecules implicated in dentinogenesis. As structural proteins they are mineralization promoters or inhibitors. They are also signaling molecules. Three different forms of dentinogenesis are identified: i) matrix vesicles are implicated in early dentin formation, ii) collagen and some proteoglycans are involved in the formation of predentin, further transformed into intertubular dentin, iii) the distal secretion of some non-collagenous ECM molecules and some serum proteins contribute to the formation of peritubular dentin.
Collapse
Affiliation(s)
- Michel Goldberg
- UMR-S 747, INSERM, Universite Paris Descartes, Paris, France.
| | | | | | | |
Collapse
|
6
|
Korkmaz Y, Klinz FJ, Beikler T, Blauhut T, Schneider K, Addicks K, Bloch W, Raab WHM. The Ca(2+)-binding protein calretinin is selectively enriched in a subpopulation of the epithelial rests of Malassez. Cell Tissue Res 2010; 342:391-400. [PMID: 21080000 DOI: 10.1007/s00441-010-1076-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 10/11/2010] [Indexed: 10/18/2022]
Abstract
During tooth development, the inner and outer enamel epithelia fuse by mitotic activity to produce a bilayered epithelial sheath termed Hertwig's epithelial root sheath (HERS). The epithelial rests of Malassez (ERM) are the developmental residues of HERS and remain in the adult periodontal ligament (PDL). Although the cellular regulation of the Ca(2+)-binding proteins parvalbumin, calbindin-D28k, and calretinin has been reported in the inner and outer enamel epithelia during tooth development, an involvement of Ca(2+)-binding proteins in the ERM has not so far been characterized. Among the three Ca(2+)-binding proteins tested (calbindin D28k, parvalbumin, calretinin), we have only been able to detect calretinin in a subpopulation of adult rat molar ERM, by using quantitative immunohistochemical and confocal immunofluorescence techniques. TrkA (a marker for ERM) is present in numerous epithelial cell clusters, whereas calretinin has been localized in the cytosol and perinuclear region of a subpopulation of TrkA-positive cells. We conclude that, in inner and outer enamel epithelial cells, Ca(2+) is regulated by calbindin, parvalbumin, and calretinin during tooth development, whereas in the ERM of adult PDL, Ca(2+) is regulated only by calretinin. The expression of Ca(2+)-binding proteins is restricted in a developmental manner in the ERM.
Collapse
Affiliation(s)
- Yüksel Korkmaz
- Department of Operative Dentistry, Periodontics and Endodontics, Heinrich Heine University, Moorenstrasse 5, 40225 Düsseldorf, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Enrich C, Rentero C, de Muga SV, Reverter M, Mulay V, Wood P, Koese M, Grewal T. Annexin A6-Linking Ca(2+) signaling with cholesterol transport. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:935-47. [PMID: 20888375 DOI: 10.1016/j.bbamcr.2010.09.015] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 09/23/2010] [Accepted: 09/24/2010] [Indexed: 11/17/2022]
Abstract
Annexin A6 (AnxA6) belongs to a conserved family of Ca(2+)-dependent membrane-binding proteins. Like other annexins, the function of AnxA6 is linked to its ability to bind phospholipids in cellular membranes in a dynamic and reversible fashion, in particular during the regulation of endocytic and exocytic pathways. High amounts of AnxA6 sequester cholesterol in late endosomes, thereby lowering the levels of cholesterol in the Golgi and the plasma membrane. These AnxA6-dependent redistributions of cellular cholesterol pools give rise to reduced cytoplasmic phospholipase A2 (cPLA(2)) activity, retention of caveolin in the Golgi apparatus and a reduced number of caveolae at the cell surface. In addition to regulating cholesterol and caveolin distribution, AnxA6 acts as a scaffold/targeting protein for several signaling proteins, the best characterized being the Ca(2+)-dependent membrane targeting of p120GAP to downregulate Ras activity. AnxA6 also stimulates the Ca(2+)-inducible involvement of PKC in the regulation of HRas and possibly EGFR signal transduction pathways. The ability of AnxA6 to recruit regulators of the EGFR/Ras pathway is likely potentiated by AnxA6-induced actin remodeling. Accordingly, AnxA6 may function as an organizer of membrane domains (i) to modulate intracellular cholesterol homeostasis, (ii) to create a scaffold for the formation of multifactorial signaling complexes, and (iii) to regulate transient membrane-actin interactions during endocytic and exocytic transport. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
Collapse
Affiliation(s)
- Carlos Enrich
- Departament de Biologia Cellular, Immunologia i Neurociències, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Abstract
The actin cytoskeleton is a malleable framework of polymerised actin monomers that may be rapidly restructured to enable diverse cellular activities such as motility, endocytosis and cytokinesis. The regulation of actin dynamics involves the coordinated activity of numerous proteins, among which members of the annexin family of Ca2+- and phospholipid-binding proteins play an important role. Although the roles of annexins in actin dynamics are not understood at a mechanistic level, annexins have the requisite properties to integrate Ca2+-signaling with actin dynamics at membrane contact sites. In this review we discuss the current state of knowledge on this topic, and consider how and where annexins may fit into the complex molecular machinery that regulates the actin cytoskeleton.
Collapse
Affiliation(s)
- Matthew J Hayes
- Division of Cell Biology, Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | | | | | | |
Collapse
|
9
|
|
10
|
Mistry D, Altini M, Coleman HG, Ali H, Maiorano E. The spatial and temporal expression of calretinin in developing rat molars (Rattus norvegicus). Arch Oral Biol 2001; 46:973-81. [PMID: 11451412 DOI: 10.1016/s0003-9969(01)00046-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Calretinin is a 29-kDa calcium-binding protein abundantly expressed in central and peripheral neural tissues. The aim here was to determine its expression during various stages of odontogenesis. Five categories of embryonic (E) and postnatal (P) rats at various ages (E17, E18, E20, P0, and P7), both male and female, were used to represent the various stages of molar tooth development. The heads of the experimental animals were harvested at the appropriate time and each was cut mid-sagittally and coronally to locate the tooth germs. Selected sections were stained immunohistochemically with polyclonal rabbit anticalretinin at a concentration of 1:25 after microwave irradiation. The results showed that calretinin is distributed widely in epithelium-derived tissues during odontogenesis in rat molar tooth germs. It was expressed focally in the dental lamina, outer enamel epithelium, stellate reticulum and stratum intermedium at different stages. In contrast, it was expressed diffusely and intensely in the inner enamel epithelium and presecretory ameloblasts, although it was discontinuous over the cusp tips. In the secretory ameloblasts, the staining was less intense, being restricted to the cytoplasm, including Tomes' processes. This distribution suggests that calretinin may play a part in enamel formation.
Collapse
Affiliation(s)
- D Mistry
- Department of Anatomical Pathology, Division of Oral Pathology, School of Oral Health Sciences, University of the Witwatersrand, 7 York Road, Parktown 2193, South Africa
| | | | | | | | | |
Collapse
|
11
|
Ohshima H, Ajima H, Kawano Y, Nozawa-Inoue K, Wakisaka S, Maeda T. Transient expression of heat shock protein (Hsp)25 in the dental pulp and enamel organ during odontogenesis in the rat incisor. ARCHIVES OF HISTOLOGY AND CYTOLOGY 2000; 63:381-95. [PMID: 11073069 DOI: 10.1679/aohc.63.381] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The expression of heat shock protein (Hsp) 25 during odontogenesis in the dental pulp and enamel organ of rat incisors was investigated by immunocytochemistry and confocal microscopy. In the process of dentin formation, immature odontoblasts first exhibited Hsp 25-immunoreactivity, and increased in immunointensity with the advance of their differentiation. In the dental pulp, in contrast, intense immunoreaction in the mesenchymal cells became weak or negative in parallel with the progress of cell differentiation. The immunoreaction for Hsp 25 in the enamel organ revealed a characteristic stage-related alteration during amelogenesis. In secretory ameloblasts, the immunoreaction for Hsp 25 was found throughout their cell bodies, intense reactivity being located near the proximal and distal terminal webs. At the maturation stage, ruffle-ended ameloblasts (RA) consistently showed Hsp 25-immunoreactivity throughout the cell bodies, whereas smooth-ended ameloblasts (SA) lacking a ruffled border were weak in immunoreaction at the distal cytoplasm. Other cellular elements of the enamel organ were negative. The subcellular localization of Hsp 25-immunoreactivity in this study appeared essentially identical to that of actin filaments as demonstrated by confocal microscopy using rhodamine-labeled phalloidin. These immunocytochemical data suggest that the Hsp 25 molecule is involved in reinforcement of the cell layer following cell movement during odontogenesis and in the formation and maintenance of the ruffled border of RA.
Collapse
Affiliation(s)
- H Ohshima
- Department of Oral Anatomy, Faculty of Dentistry, Niigata University, Gakkocho-dori, Japan.
| | | | | | | | | | | |
Collapse
|
12
|
Szewczyk A, Pikuła S. Adenosine 5'-triphosphate: an intracellular metabolic messenger. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1365:333-53. [PMID: 9711292 DOI: 10.1016/s0005-2728(98)00094-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- A Szewczyk
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland.
| | | |
Collapse
|
13
|
Bandorowicz-Pikuła J. A nucleotide-binding domain of porcine liver annexin VI. Proteolysis of annexin VI labelled with 8-azido-ATP, purification by affinity chromatography on ATP-agarose, and fluorescence studies. Mol Cell Biochem 1998; 181:11-20. [PMID: 9562237 DOI: 10.1023/a:1006854808851] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Porcine liver annexin VI (AnxVI) of Mr 68.000 is an ATP-binding protein as evidenced by specific and saturable UV-dependent labelling with 8-azido-[gamma-32P]ATP or the fluorescent analog of ATP, 2'-(or 3')-O-(2,4,6-trinitrophenyl)adenosine triphosphate and by binding of AnxVI to ATP-agarose. These characteristics of purified AnxVI were used to identify and characterize preliminary nucleotide-binding domain of the protein. AnxVI labelled with 8-azido-ATP was subjected to limited proteolysis and the proteolytic fragments of AnxVI that retained the covalently-bound nucleotide were separated by means of gel electrophoresis and visualized by exposure of the gel to a phosphor storage screen. It was found that the AnxVI proteolytic fragments of Mr 34-36.000 and smaller retained the nucleotide. In a reciprocal experiment, AnxVI was digested with proteolytic enzymes and in an ATP eluate from an ATP-agarose column protein fragments of similar Mr to these labelled with 8-azido-ATP were identified. The extent of AnxVI labelling with 8-azido-ATP and the distribution of proteolytic fragments varied upon calcium concentration. These results lead to the conclusion that there is a nucleotide-binding domain within the AnxVI molecule that is functionally similar to the nucleotide-binding domains of other nucleotide-binding proteins. The nucleotide-binding domain is located close to the tryptophan residue 343 of AnxVI and in close vicinity to the Ca2+- and phospholipid-binding sites of the protein. This is confirmed by the observation that the tryptophan fluorescence intensity of AnxVI decreases in the presence of a fluorescence analog of ATP in a calcium-dependent manner, due to the quenching properties of the nucleotide and/or fluorescence energy transfer from AnxVI tryptophan to fluorophore. Both processes were modulated by the presence of phospholipid molecules.
Collapse
Affiliation(s)
- J Bandorowicz-Pikuła
- Department of Cellular Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
| |
Collapse
|
14
|
Koumanov K, Wolf C, Béreziat G. Modulation of human type II secretory phospholipase A2 by sphingomyelin and annexin VI. Biochem J 1997; 326 ( Pt 1):227-33. [PMID: 9337873 PMCID: PMC1218659 DOI: 10.1042/bj3260227] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Conjectural results have been reported on the capacity of inflammatory secreted phospholipase A2 (sPLA2) to hydrolyse mammalian membrane phospholipids. Development of an assay based on the release of non-esterified fatty acids by the enzyme acting on the organized phospholipid mixture constituting the membrane matrix has led to the identification of two prominent effectors, sphingomyelin (SPH) and annexin. Recombinant human type II sPLA2 hydrolyses red-cell membrane phospholipids with a marked preference for the inner leaflet. This preference is apparently related to the high content of SPH in the outer leaflet, which inhibits sPLA2. This inhibition by SPH is specific for sPLA2. Cholesterol counteracts the inhibition of sPLA2 by SPH, suggesting that the SPH-to-cholesterol ratio accounts in vivo for the variable susceptibility of cell membranes to sPLA2. Different effects were observed of the presence of the non-hydrolysable D-alpha-dipalmitoyl phosphatidylcholine (D-DPPC), which renders the membranes rigid but does not inhibit sPLA2. Annexin VI was shown, along with other annexins, to inhibit sPLA2 activity by sequestering the phospholipid substrate. The present study has provided the first evidence that annexin VI, in concentrations that inhibit hydrolysis of purified phospholipid substrates, stimulated the hydrolysis of membrane phospholipids by sPLA2. The activation requires the presence of membrane proteins. The effect is specific for type II sPLA2 and is not reproducible with type I PLA2. The activation by annexin VI of sPLA2 acting on red cell membranes results in the preferential release of polyunsaturated fatty acids. It suggests that type II sPLA2, in conjunction with annexin VI, might be involved in the final step of endocytosis and/or exocytosis providing the free polyunsaturated fatty acids acting synergistically to cause membrane fusion.
Collapse
Affiliation(s)
- K Koumanov
- Laboratoire de Biochimie, URA CNRS 1283, Faculté de Médecine Saint Antoine, Université Pierre et Marie Curie, Paris, France
| | | | | |
Collapse
|
15
|
Bandorowicz-Pikuła J, Awasthi YC. Interaction of annexins IV and VI with ATP. An alternative mechanism by which a cellular function of these calcium- and membrane-binding proteins is regulated. FEBS Lett 1997; 409:300-6. [PMID: 9202166 DOI: 10.1016/s0014-5793(97)00534-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Annexin VI from porcine liver can be photoaffinity-labeled with 8-azido-[gamma-32P]ATP in a concentration-dependent, saturable manner. The extent of labeling varied with the concentration of calcium. The dissociation constant for the nucleotide was found to be in the range reported for ATP-binding proteins. The ATP analog, 2'-(or 3')-O-(2,4,6-trinitrophenyl)-adenosine 5'-triphosphate, also bound to AnxVI, as indicated by shift in its fluorescence spectra in the presence of protein. Any significant 8-azido-ATP or TNP-ATP binding was not observed with AnxIV. ATP modulated the binding of AnxVI to erythrocyte membrane and increased the Ca2+ concentration required for half-maximal binding of AnxVI to F-actin.
Collapse
Affiliation(s)
- J Bandorowicz-Pikuła
- Department of Cellular Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland.
| | | |
Collapse
|
16
|
Hubbard MJ. Abundant calcium homeostasis machinery in rat dental enamel cells. Up-regulation of calcium store proteins during enamel mineralization implicates the endoplasmic reticulum in calcium transcytosis. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 239:611-23. [PMID: 8774704 DOI: 10.1111/j.1432-1033.1996.0611u.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
UNLABELLED Enamel cells handle large amounts of calcium, particularly during the developmental phase (termed maturation) when dental enamel is hypermineralized. The extent of intracellular calcium burden, and the nature of calcium homeostasis machinery used to accommodate it, are largely unknown. Here, the calcium-binding capacity of enamel cell cytosol was found to increase during development, in parallel with the putative transcellular flux of calcium. At maturation, the abundance of calcium-binding proteins in enamel cells exceeded that in brain and other established calcium-oriented tissues, which implies a large calcium burden. A search for likely cytosolic calcium transporters revealed only one high-affinity calcium-binding protein (12 kDa, distinguished from alpha-parvalbumin) that was up-regulated during maturation, but its low abundance (0.02% of soluble protein) precluded a major calcium transport or cytoprotective role. Two low-affinity calcium-binding proteins up-regulated during maturation (by 1.8-fold and 2.1-fold respectively) were identified as calreticulin and endoplasmin, both residents of the endoplasmic reticulum. Together, calreticulin and endoplasmin constituted an exceptionally high proportion (5%) of soluble protein during maturation, which gives an inferred calcium capacity 67-fold higher than that of the principal cytosolic calcium-binding protein. 28-kDa calbindin. Evidence that endoplasmin expression varied inversely with serum calcium concentration, and that the inositol trisphosphate receptor also was highly expressed during maturation, supported the novel hypothesis that non-mitochondrial calcium stores play a major role in transcellular calcium transport. IN CONCLUSION (a) enamel cells contain a general high abundance of calcium homeostasis proteins, consistent with a heavy intracellular calcium burden; (b) the expression pattern (phenotype) of calcium-binding proteins varies with enamel cell function; (c) enamel cells appear to contain unusually large non-mitochondrial calcium stores; (d) contrary to the prevailing view that calcium passes mainly through the cytosol of calcium-transporting cells, the findings imply a route through the endoplasmic reticulum. This study gives novel information about how a highly calcium-oriented tissue avoids calcium toxicity, and provides a new focus for investigations into the mechanisms of transcellular calcium transport.
Collapse
Affiliation(s)
- M J Hubbard
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| |
Collapse
|
17
|
Chen WY, Nanci A, Smith CE. Immunoblotting studies on artifactual contamination of enamel homogenates by albumin and other proteins. Calcif Tissue Int 1995; 57:145-51. [PMID: 7584875 DOI: 10.1007/bf00298435] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The reason for the presence of albumin and other serum, cytoskeletal, cytosolic, and extracellular matrix proteins in enamel fractions was investigated by immunoblotting using homogenates prepared from freeze-dried and freshly dissected rat incisors, and antibodies capable of resolving at least 1 ng of the primary antigen. The data indicated that most of the 16 antibodies examined in this study reacted with antigens present only within "cell" homogenates (enamel organ cells + adhering labial connective tissue and blood vessels). One exception was rat serum albumin which was detected routinely in enamel homogenates prepared from freshly dissected, wiped incisors but rarely within enamel homogenates prepared from freeze-dried incisors. Another exception was calbindin-D 28 kDa which was consistently found within secretory stage enamel homogenates irrespective of preparative technique. A third exception was enamel proteins (amelogenins) which were enriched in secretory and early maturation stage enamel homogenates compared with cell homogenates and distributed as multiple molecular weight, antigenic bands in enamel homogenates (14-30 kDa), but mostly as a single antigenic band in cell homogenates (near 27 kDa). Overall, the results of this study suggest that developing rat incisor enamel naturally contains few exogenous proteins such as albumin. High concentrations of albumin (or other serum proteins) in crude homogenates, or purified fractions, derive mostly from blood and/or tissue fluids soaking into the enamel during sample preparation. This type of artifact can be avoided by using freeze-dried teeth for biochemical analyses.
Collapse
Affiliation(s)
- W Y Chen
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | | | | |
Collapse
|
18
|
Rainteau D, Mansuelle P, Rochat H, Weinman S. Characterization and ultrastructural localization of annexin VI from mitochondria. FEBS Lett 1995; 360:80-4. [PMID: 7875306 DOI: 10.1016/0014-5793(95)00087-p] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Annexin VI, a member of a family of related intracellular proteins that associate reversibly with membrane phospholipids in a Ca(2+)-dependent manner, has been purified from bovine liver mitochondria and characterized. Moreover, biochemical and immunocytochemical lines of evidence are presented which strongly suggest that annexin VI is closely associated with the cristae in the inner membrane of mitochondria. These findings are consistent with a calcium channel activity of annexin VI in mitochondria.
Collapse
Affiliation(s)
- D Rainteau
- Département de Biochimie, UFR Biomédicale des Saints-Pères, Université René Descartes, Paris, France
| | | | | | | |
Collapse
|
19
|
Weinman JS, Feinberg JM, Rainteau DP, Gaspera BD, Weinman SJ. Annexins in rat enterocyte and hepatocyte: an immunogold electron-microscope study. Cell Tissue Res 1994; 278:389-97. [PMID: 8001090 DOI: 10.1007/bf00414181] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In the present study, immunogold labeling of ultrathin sections of rat small intestine and liver has been used to obtain insights into the ultrastructural localization and possible functions of annexins. In enterocytes, annexins II, IV, and VI are found at the periphery of the core of each microvillus and of the rootlets, but are absent from the interrootlet space. Annexins II, IV, and VI are also observed close to the interdigitated plasma membrane. In hepatocytes, only annexin VI is found to be concentrated within the microvilli in the bile canaliculi, on the inner face of the sinusoidal cell surface, particularly in the space of Disse, and all along the plasma membrane. Annexin VI is also detected in mitochondria of enterocytes and hepatocytes. These localizations are in agreement with the concept of a close calcium-dependent association of annexins with membranes and cytoskeletal proteins, particularly with actin. Moreover, they support the hypothesis of an involvement of annexins in exocytotic and endocytotic processes, which take place in epithelial cells.
Collapse
Affiliation(s)
- J S Weinman
- Département de Biochimie, UFR Biomédicale des Saints-Pères, Université René Descartes, Paris, France
| | | | | | | | | |
Collapse
|
20
|
Tagoe CE, Boustead CM, Higgins SJ, Walker JH. Characterization and immunolocalization of rat liver annexin VI. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1192:272-80. [PMID: 8018708 DOI: 10.1016/0005-2736(94)90128-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Annexin VI has been purified to homogeneity from rat liver and monospecific antibodies have been produced. The antibodies have been used for immunoblot analysis of rat tissues. Annexin VI is present in most tissues, with particularly high concentrations in liver, spleen, muscle, and intestine. In liver, annexin VI constitutes approximately 0.25% of total cellular protein. Immunohistochemical studies have located annexin VI on plasma membranes of hepatocytes with enhanced concentration on bile canaliculi. Annexin VI binds in a Ca(2+)-dependent manner to a sub-cellular fraction containing membranes. In the presence of physiological concentrations of ATP, the free Ca2+ concentration required for half-maximal binding of annexin VI to membranes is significantly reduced. While annexin VI binds in vitro to membranes in the presence of Ca2+, in rat liver about 31% of the annexin VI is associated with membranes in a Ca(2+)-independent manner and its solubilization requires the presence of Triton X-100. However, studies using Triton X-114 showed no increase in the hydrophobicity of this fraction of the protein compared to the purified EGTA-soluble annexin VI.
Collapse
Affiliation(s)
- C E Tagoe
- Department of Biochemistry and Molecular Biology, University of Leeds, UK
| | | | | | | |
Collapse
|
21
|
|
22
|
Linde A, Goldberg M. Dentinogenesis. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 1993; 4:679-728. [PMID: 8292714 DOI: 10.1177/10454411930040050301] [Citation(s) in RCA: 302] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The formation of dentin, dentinogenesis, comprises a sophisticated interplay between several factors in the tissue, cellular as well as extracellular. Dentin may be regarded as a calcified connective tissue. In this respect, as well as in its mode of formation, it is closely related to bone. Using dentinogenesis as an experimental model to study biomineralization provides several practical advantages, and the results may be extrapolated to understand similar processes in other tissues, primarily bone. After describing dentin structure and composition, this review discusses items such as the morphology of dentinogenesis; the dentinogenically active odontoblast, transport, and concentrations of mineral ions; the constituents of the dentin organic matrix; and the presumed mechanisms involved in mineral formation.
Collapse
Affiliation(s)
- A Linde
- Department of Oral Biochemistry, Faculty of Odontology, University of Göteborg, Sweden
| | | |
Collapse
|
23
|
Davideau JL, Celio MR, Hotton D, Berdal A. Developmental pattern and subcellular localization of parvalbumin in the rat tooth germ. Arch Oral Biol 1993; 38:707-15. [PMID: 8215995 DOI: 10.1016/0003-9969(93)90011-a] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The EF-hand calcium-binding protein parvalbumin has been extensively studied in nerve and muscle cells. Its possible role in biomineralization during tooth development was here investigated by determining its subcellular localization by immunogold cytochemistry. The developmental sequences of amelogenesis and dentinogenesis were studied in rat molars, and in continuously growing rat incisors. The findings confirm that parvalbumin is a nuclear and a cytosolic protein, not associated with any particular intracellular organelle. Epithelial and mesenchymal undifferentiated cells contained no specific parvalbumin immunolabelling. In differentiated ameloblasts, secretory-pole (Tomes' process) formation was associated with a proximal-distal gradient of parvalbumin labelling. But after the Tomes' process had formed, parvalbumin was evenly distributed throughout the cell. The parvalbumin contents of ruffle-ended and smooth-ended ameloblasts appeared to be very different. Differentiated odontoblasts were less heavily labelled than ameloblasts, and the label was restricted to the cell body during the whole of dentinogenesis. These data suggest that parvalbumin could contribute to membrane plasticity during differentiation, as shown during dendritic growth in the nervous cells. Moreover, as may occur in excitable cells, parvalbumin could buffer calcium specifically in the cells producing mineralized enamel and dentine during the later stages of tooth development.
Collapse
Affiliation(s)
- J L Davideau
- INSERM U 120, Hôpital Robert Debré, Paris, France
| | | | | | | |
Collapse
|
24
|
Kuijpers GA, Lee G, Pollard HB. Immunolocalization of synexin (annexin VII) in adrenal chromaffin granules and chromaffin cells: evidence for a dynamic role in the secretory process. Cell Tissue Res 1992; 269:323-30. [PMID: 1423500 DOI: 10.1007/bf00319624] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Synexin (annexin VII) is a Ca(2+)- and phospholipid-binding protein which has been proposed to play a role in Ca(2+)-dependent membrane fusion processes. Using a monoclonal antibody against synexin, Mab 10E7, and immunogold, we carried out a semiquantitative localization study of synexin in bovine adrenal medullary chromaffin granules, and in resting and nicotine-stimulated adrenal chromaffin cells. Isolated chromaffin granules contained very little synexin, whereas chromaffin granules aggregated with synexin (24 micrograms/mg) and Ca2+ (1 mM) clearly showed synexin-associated immunogold particles in the vicinity of the granule membrane (1.88 gold particles per granule profile). In isolated, cultured adrenal chromaffin cells, synexin was present in the nucleus (5.5 particles/microns 2) and in the cytosol (5.3 particles/microns 2), but mainly around the granule membrane in the granular cell area (11.7 particles/microns 2). During the active phase of cholinergically stimulated catecholamine secretion, the amount of synexin label was reduced by 33% in the nucleus, by 23% in the cytosol, and by 51% in the granule area. The plasma membrane contained a small amount of synexin, which did not significantly change upon stimulation of the cells. We conclude that synexin is involved in the secretory process in chromaffin cells.
Collapse
Affiliation(s)
- G A Kuijpers
- Laboratory of Cell Biology and Genetics, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | | | | |
Collapse
|