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Hossain KR, Li X, Zhang T, Paula S, Cornelius F, Clarke RJ. Polarity of the ATP binding site of the Na +,K +-ATPase, gastric H +,K +-ATPase and sarcoplasmic reticulum Ca 2+-ATPase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183138. [PMID: 31790695 DOI: 10.1016/j.bbamem.2019.183138] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/15/2019] [Accepted: 11/27/2019] [Indexed: 11/18/2022]
Abstract
A fluorescence ratiometric method utilizing the probe eosin Y is presented for estimating the ATP binding site polarity of P-type ATPases in different conformational states. The method has been calibrated by measurements in a series of alcohols and tested using complexation of eosin Y with methyl-β-cyclodextrin. The results obtained with the Na+,K+-, H+,K+- and sarcoplasmic reticulum Ca2+-ATPases indicate that the ATP binding site, to which eosin is known to bind, is significantly more polar in the case of the Na+,K+- and H+,K+-ATPases compared to the Ca2+-ATPase. This result was found to be consistent with docking calculations of eosin with the E2 conformational state of the Na+,K+-ATPase and the Ca2+-ATPase. Fluorescence experiments showed that eosin binds significantly more strongly to the E1 conformation of the Na+,K+-ATPase than the E2 conformation, but in the case of the Ca2+-ATPase both fluorescence experiments and docking calculations showed no significant difference in binding affinity between the two conformations. This result could be due to the fact that, in contrast to the Na+,K+- and H+,K+-ATPases, the E2-E1 transition of the Ca2+-ATPase does not involve the movement of a lysine-rich N-terminal tail which may affect the overall enzyme conformation. Consistent with this hypothesis, the eosin affinity of the E1 conformation of the Na+,K+-ATPase was significantly reduced after N-terminal truncation. It is suggested that changes in conformational entropy of the N-terminal tail of the Na+, K+- and the H+,K+-ATPases during the E2-E1 transition could affect the thermodynamic stability of the E1 conformation and hence its ATP binding affinity.
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Affiliation(s)
- K R Hossain
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
| | - X Li
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
| | - T Zhang
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - S Paula
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - F Cornelius
- Department of Biomedicine, University of Aarhus, DK-8000 Aarhus C, Denmark
| | - R J Clarke
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia; The University of Sydney Nano Institute, Sydney, NSW 2006, Australia.
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Yoshida K, Shiba K, Sakamoto A, Ikenaga J, Matsunaga S, Inaba K, Yoshida M. Ca 2+ efflux via plasma membrane Ca 2+-ATPase mediates chemotaxis in ascidian sperm. Sci Rep 2018; 8:16622. [PMID: 30413746 PMCID: PMC6226504 DOI: 10.1038/s41598-018-35013-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 10/30/2018] [Indexed: 12/15/2022] Open
Abstract
When a spermatozoon shows chemotactic behavior, transient [Ca2+]i increases in the spermatozoon are induced by an attractant gradient. The [Ca2+]i increase triggers a series of stereotypic responses of flagellar waveforms that comprise turning and straight-swimming. However, the molecular mechanism of [Ca2+]i modulation controlled by the attractants is not well defined. Here, we examined receptive mechanisms for the sperm attractant, SAAF, in the ascidian, Ciona intestinalis, and identified a plasma membrane Ca2+-ATPase (PMCA) as a SAAF-binding protein. PMCA is localized in sperm flagella membranes and seems to interact with SAAF through basic amino acids located in the second and third extracellular loops. ATPase activity of PMCA was enhanced by SAAF, and PMCA inhibitors, 5(6)-Carboxyeosin diacetate and Caloxin 2A1, inhibited chemotactic behavior of the sperm. Furthermore, Caloxin 2A1 seemed to inhibit efflux of [Ca2+]i in the sperm, and SAAF seemed to competitively reduce the effect of Caloxin 2A1. On the other hand, chemotactic behavior of the sperm was disordered not only at low-Ca2+, but also at high-Ca2+ conditions. Thus, PMCA is a potent candidate for the SAAF receptor, and direct control of Ca2+ efflux via PMCA is a fundamental mechanism to mediate chemotactic behavior in the ascidian spermatozoa.
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Affiliation(s)
- Kaoru Yoshida
- Faculty of Biomedical Engineering, Toin University of Yokohama, Yokohama, Kanagawa, 225-8503, Japan
| | - Kogiku Shiba
- Misaki Marine Biological Station, School of Science, the University of Tokyo, Miura, Kanagawa, 238-0225, Japan
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, 415-0025, Japan
| | - Ayako Sakamoto
- Misaki Marine Biological Station, School of Science, the University of Tokyo, Miura, Kanagawa, 238-0225, Japan
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Jumpei Ikenaga
- Misaki Marine Biological Station, School of Science, the University of Tokyo, Miura, Kanagawa, 238-0225, Japan
| | - Shigeru Matsunaga
- Misaki Marine Biological Station, School of Science, the University of Tokyo, Miura, Kanagawa, 238-0225, Japan
- Central Research Laboratory, Hamamatsu Photonics K.K., Hamamatsu, Shizuoka, 434-8601, Japan
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, 415-0025, Japan
| | - Manabu Yoshida
- Misaki Marine Biological Station, School of Science, the University of Tokyo, Miura, Kanagawa, 238-0225, Japan.
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Hepatocyte nuclear factor 1A deficiency causes hemolytic anemia in mice by altering erythrocyte sphingolipid homeostasis. Blood 2017; 130:2786-2798. [PMID: 29109103 DOI: 10.1182/blood-2017-03-774356] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 10/25/2017] [Indexed: 12/18/2022] Open
Abstract
The hepatocyte nuclear factor (HNF) family regulates complex networks of metabolism and organ development. Human mutations in its prototypical member HNF1A cause maturity-onset diabetes of the young (MODY) type 3. In this study, we identified an important role for HNF1A in the preservation of erythrocyte membrane integrity, calcium homeostasis, and osmotic resistance through an as-yet unrecognized link of HNF1A to sphingolipid homeostasis. HNF1A-/- mice displayed microcytic hypochromic anemia with reticulocytosis that was partially compensated by avid extramedullary erythropoiesis at all erythroid stages in the spleen thereby excluding erythroid differentiation defects. Morphologically, HNF1A-/- erythrocytes resembled acanthocytes and displayed increased phosphatidylserine exposure, high intracellular calcium, and elevated osmotic fragility. Sphingolipidome analysis by mass spectrometry revealed substantial and tissue-specific sphingolipid disturbances in several tissues including erythrocytes with the accumulation of sphingosine as the most prominent common feature. All HNF1A-/- erythrocyte defects could be simulated by exposure of wild-type (WT) erythrocytes to sphingosine in vitro and attributed in part to sphingosine-induced suppression of the plasma-membrane Ca2+-ATPase activity. Bone marrow transplantation rescued the anemia phenotype in vivo, whereas incubation with HNF1A-/- plasma increased the osmotic fragility of WT erythrocytes in vitro. Our data suggest a non-cell-autonomous erythrocyte defect secondary to the sphingolipid changes caused by HNF1A deficiency. Transcriptional analysis revealed 4 important genes involved in sphingolipid metabolism to be deregulated in HNF1A deficiency: Ormdl1, sphingosine kinase-2, neutral ceramidase, and ceramide synthase-5. The considerable erythrocyte defects in murine HNF1A deficiency encourage clinical studies to explore the hematological consequences of HNF1A deficiency in human MODY3 patients.
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Kubala M, Čechová P, Geletičová J, Biler M, Štenclová T, Trouillas P, Biedermann D. Flavonolignans As a Novel Class of Sodium Pump Inhibitors. Front Physiol 2016; 7:115. [PMID: 27065883 PMCID: PMC4812144 DOI: 10.3389/fphys.2016.00115] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 03/14/2016] [Indexed: 11/13/2022] Open
Abstract
We examined the inhibitory effects of three flavonolignans and their dehydro- derivatives, taxifolin and quercetin on the activity of the Na+/K+-ATPase (NKA). The flavonolignans silychristin, dehydrosilychristin and dehydrosilydianin inhibited NKA with IC50 of 110 ± 40 μM, 38 ± 8 μM, and 36 ± 14 μM, respectively. Using the methods of molecular modeling, we identified several possible binding sites for these species on NKA and proposed the possible mechanisms of inhibition. The binding to the extracellular- or cytoplasmic C-terminal sites can block the transport of cations through the plasma membrane, while the binding on the interface of cytoplasmic domains can inhibit the enzyme allosterically. Fluorescence spectroscopy experiments confirmed the interaction of these three species with the large cytoplasmic segment connecting transmembrane helices 4 and 5 (C45). The flavonolignans are distinct from the cardiac glycosides that are currently used in NKA treatment. Because their binding sites are different, the mechanism of inhibition is different as well as the range of active concentrations, one can expect that these new NKA inhibitors would exhibit also a different biomedical actions than cardiac glycosides.
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Affiliation(s)
- Martin Kubala
- Department of Biophysics, Faculty of Science, Centre of Region Haná for Biotechnological and Agricultural Research, Palacký University Olomouc, Czech Republic
| | - Petra Čechová
- Department of Biophysics, Faculty of Science, Centre of Region Haná for Biotechnological and Agricultural Research, Palacký University Olomouc, Czech Republic
| | - Jaroslava Geletičová
- Department of Biophysics, Faculty of Science, Centre of Region Haná for Biotechnological and Agricultural Research, Palacký University Olomouc, Czech Republic
| | - Michal Biler
- Department of Biophysics, Faculty of Science, Centre of Region Haná for Biotechnological and Agricultural Research, Palacký UniversityOlomouc, Czech Republic; INSERM UMR 850, School of Pharmacy, University LimogesLimoges, France
| | - Tereza Štenclová
- Department of Biophysics, Faculty of Science, Centre of Region Haná for Biotechnological and Agricultural Research, Palacký University Olomouc, Czech Republic
| | - Patrick Trouillas
- INSERM UMR 850, School of Pharmacy, University LimogesLimoges, France; Department of Physical Chemistry, Faculty of Science, Regional Centre of Advanced Technologies and Materials, Palacký UniversityOlomouc, Czech Republic
| | - David Biedermann
- Laboratory of Biotransformation, Institute of Microbiology, Czech Academy of Sciences Prague, Czech Republic
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Correlation among phenyltins molecular properties, degradation and cellular influences on Bacillus thuringiensis in the presence of biosurfactant. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2015.09.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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