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Nawaly H, Matsui H, Tsuji Y, Iwayama K, Ohashi H, Nakajima K, Matsuda Y. Multiple plasma membrane SLC4s contribute to external HCO3- acquisition during CO2 starvation in the marine diatom Phaeodactylum tricornutum. J Exp Bot 2023; 74:296-307. [PMID: 36124754 DOI: 10.1093/jxb/erac380] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 09/16/2022] [Indexed: 06/15/2023]
Abstract
The availability of CO2 is one of the restrictions on aquatic photosynthesis. Solute carrier (SLC) 4-2, a plasma membrane HCO3- transporter has previously been identified in the marine diatom Phaeodactylum tricornutum. In this study, we discovered two paralogs, PtSLC4-1 and PtSLC4-4, that are both localized at the plasma membrane. Their overexpression stimulated HCO3- uptake, and this was inhibited by the anion channel blocker 4,4´-diisothiocyanostilbene-2,2´-disulfonic (DIDS). Similarly to SLC4-2, PtSLC4-1 specifically required Na+ of ~100 mM for its maximum HCO3- transport activity. Unlike PtSLC4-1 and PtSLC4-2, the HCO3- transport of PtSLC4-4 depended equally on Na+, K+, or Li+, suggesting its broad selectivity for cations. Transcript analyses indicated that PtSLC4-1 was the most abundant HCO3- transporter under CO2 concentrations below atmospheric levels, while PtSLC4-4 showed little transcript induction under atmospheric CO2 but transient induction to comparable levels to PtSLC4-1 during the initial acclimation stage from high CO2 (1%) to very low CO2 (<0.002%). Our results strongly suggest a major HCO3- transport role of PtSLC4-1 with a relatively minor role of PtSLC4-2, and that PtSLC4-4 operates under severe CO2 limitation unselectively to cations when the other SLC4s do not function to support HCO3- uptake.
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Affiliation(s)
- Hermanus Nawaly
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Hiroaki Matsui
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Yoshinori Tsuji
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Kazufumi Iwayama
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Hiroki Ohashi
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Kensuke Nakajima
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Yusuke Matsuda
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
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Bu G, Parrish S, Gleason PR, Nielsen DR, Nannenga BL. Heterologous expression and purification of the bicarbonate transporter BicA from Synechocystis sp. PCC 6803. Protein Expr Purif 2020; 175:105716. [PMID: 32738437 DOI: 10.1016/j.pep.2020.105716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 06/25/2020] [Accepted: 07/22/2020] [Indexed: 11/18/2022]
Abstract
The high-flux/low-affinity cyanobacterial bicarbonate transporter BicA is a member of sulfate permease/solute carrier 26 (SulP/SLC26) family and plays a major role in cyanobacterial inorganic carbon uptake. In order to study this important membrane protein, robust platforms for over-expression and protocols for purification are required. In this work we have optimized the expression and purification of BicA from strain Synechocystis sp. PCC 6803 (BicA6803) in Escherichia coli. It was determined that expression with C43 (DE3) Rosetta2 at 37 °C produced the highest levels of over-expressed BicA6803 relative to other strains screened, and membrane solubilization with n-dodecyl-β-d-maltopyranoside facilitated the purification of high levels of stable and homogenous BicA6803. Using these expression and purification strategies, the final yields of purified BicA were 6.5 ± 1.0 mg per liter of culture.
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Affiliation(s)
- Guanhong Bu
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, 85287, USA; Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Sydney Parrish
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, 85287, USA
| | - Patrick R Gleason
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA; Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ, 85278, USA
| | - David R Nielsen
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, 85287, USA
| | - Brent L Nannenga
- Chemical Engineering, School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, 85287, USA; Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.
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Wang M, Wu H, Liu Y, Chen LM. Activation of mouse NBCe1-B by Xenopus laevis and mouse IRBITs: Role of the variable Nt appendage of IRBITs. Biochim Biophys Acta Biomembr 2020; 1862:183240. [PMID: 32119862 DOI: 10.1016/j.bbamem.2020.183240] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/19/2020] [Accepted: 02/20/2020] [Indexed: 12/24/2022]
Abstract
The IP3 receptor binding protein released with inositol 1,4,5-trisphosphate (IRBIT) plays important roles in the regulation of intracellular Ca2+ signaling and intracellular pH. The mammals express two IRBIT paralogs, i.e., IRBIT1 (encoded by AHCYL1) and IRBIT2 (encoded by AHCYL2). The clawed frog Xenopus laevis oocyte is widely used for biophysical studies on ion channels and transporters. It remains unknown whether endogenous IRBIT is expressed in Xenopus oocytes. Here, we cloned from frog oocyte irbit2.L and irbit2.S, orthologs of mammalian IRBIT2. When over-expressed, the frog IRBITs powerfully stimulate the electrogenic Na+/HCO3- cotransporter NBCe1-B as mouse IRBIT2-V2 does. Expression of an isolated Nt fragment of NBCe1-B containing the IRBIT-binding domain greatly decreases NBCe1-B activity in oocytes, suggesting that the basal activity of NBCe1-B contains a large component derived from the stimulation by endogenous frog IRBIT. The frog IRBITs are highly homologous to the mammalian ones in the carboxyl-terminal region, but varies greatly in the amino-terminal (Nt) appendage. Interestingly, truncation study showed that the Nt appendage of IRBIT1 and the long Nt appendage of IRBIT2-V2 modestly enhance, whereas the short Nt appendage of IRBIT2-V4 greatly inhibits the functional interaction between IRBIT and NBCe1-B. Finally, Ala-substitution of Ser68, a key phosphorylation site in the PEST domain of IRBIT, causes distinct functional consequences depending on the structural context of the Nt appendage in different IRBIT isoforms. We conclude that the Nt appendage of IRBITs is not necessary for, but plays an important regulatory role in the functional interaction between IRBIT and NBCe1-B.
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Affiliation(s)
- Meng Wang
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science & Technology, Huazhong University of Science & Technology, Wuhan, Hubei 430074, China
| | - Han Wu
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science & Technology, Huazhong University of Science & Technology, Wuhan, Hubei 430074, China
| | - Ying Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science & Technology, Huazhong University of Science & Technology, Wuhan, Hubei 430074, China.
| | - Li-Ming Chen
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science & Technology, Huazhong University of Science & Technology, Wuhan, Hubei 430074, China.
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Yamano T, Toyokawa C, Fukuzawa H. High-resolution suborganellar localization of Ca 2+-binding protein CAS, a novel regulator of CO 2-concentrating mechanism. Protoplasma 2018; 255:1015-1022. [PMID: 29372336 DOI: 10.1007/s00709-018-1208-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/10/2018] [Indexed: 05/19/2023]
Abstract
Many aquatic algae induce a CO2-concentrating mechanism (CCM) associated with active inorganic carbon transport to maintain high photosynthetic affinity using dissolved inorganic carbon even in low-CO2 (LC) conditions. In the green alga Chlamydomonas reinhardtii, a Ca2+-binding protein CAS was identified as a novel factor regulating the expression of CCM-related proteins including bicarbonate transporters. Although previous studies revealed that CAS associates with the thylakoid membrane and changes its localization in response to CO2 and light availability, its detailed localization in the chloroplast has not been examined in vivo. In this study, high-resolution fluorescence images of CAS fused with a Chlamydomonas-adapted fluorescence protein, Clover, were obtained by using a sensitive hybrid detector and an image deconvolution method. In high-CO2 (5% v/v) conditions, the fluorescence signals of Clover displayed a mesh-like structure in the chloroplast and part of the signals discontinuously overlapped with chlorophyll autofluorescence. The fluorescence signals gathered inside the pyrenoid as a distinct wheel-like structure at 2 h after transfer to LC-light condition, and then localized to the center of the pyrenoid at 12 h. These results suggest that CAS could move in the chloroplast along the thylakoid membrane in response to lowering CO2 and gather inside the pyrenoid during the operation of the CCM.
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Affiliation(s)
- Takashi Yamano
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan
| | - Chihana Toyokawa
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan
| | - Hideya Fukuzawa
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan.
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Tsuji Y, Mahardika A, Matsuda Y. Evolutionarily distinct strategies for the acquisition of inorganic carbon from seawater in marine diatoms. J Exp Bot 2017; 68:3949-3958. [PMID: 28398591 PMCID: PMC5853789 DOI: 10.1093/jxb/erx102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/07/2017] [Indexed: 05/07/2023]
Abstract
The acquisition of dissolved inorganic carbon (DIC) in CO2-limited seawater is a central issue to understand in marine primary production. We previously demonstrated the occurrence of direct HCO3- uptake by solute carrier (SLC) 4 transporters in a diatom, a major marine primary producer. Homologs of SLC are found in both centric and pennate marine diatoms, suggesting that SLC transporters are generally conserved. Here, the generality of SLC-mediated DIC uptake in diatoms was examined using an SLC inhibitor, diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS), and an inhibitor of external carbonic anhydrase, acetazolamide. DIDS suppressed high-DIC-affinity photosynthesis in the pennate diatom Phaeodactylum tricornutum and the centric diatom Chaetoceros muelleri, but there was no effect on either the pennate Cylindrotheca fusiformis or the centric Thalassiosira pseudonana. Interestingly, the DIC affinity of DIDS-insensitive strains was sensitive to treatment with up to 100 μM acetazolamide, displaying a 2-4-fold increase in K0.5[DIC]. In contrast, acetazolamide did not affect the DIDS-sensitive group. These results indicate the occurrence of two distinct strategies for DIC uptake-one primarily facilitated by SLC and the other being passive CO2 entry facilitated by external carbonic anhydrase. The phylogenetic independence of these strategies suggests that environmental demands drove the evolution of distinct DIC uptake mechanisms in diatoms.
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Affiliation(s)
- Yoshinori Tsuji
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda, Hyogo, Japan
| | - Anggara Mahardika
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda, Hyogo, Japan
| | - Yusuke Matsuda
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda, Hyogo, Japan
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Lee HJ, Kwon MH, Lee S, Hall RA, Yun CC, Choi I. Systematic family-wide analysis of sodium bicarbonate cotransporter NBCn1/SLC4A7 interactions with PDZ scaffold proteins. Physiol Rep 2014; 2:2/5/e12016. [PMID: 24844638 PMCID: PMC4098744 DOI: 10.14814/phy2.12016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
NBCn1 (SLC4A7) plays a role in transepithelial HCO3 (-) movement and intracellular pH maintenance in many tissues. In this study, we searched PDZ proteins capable of binding to NBCn1. We screened a protein array membrane, on which 96 different class I PDZ protein peptides were blotted, with the C-terminal domain of NBCn1 fused to GST. Thirteen proteins were identified in these screens: MAGI-3, NHERF-1, NHERF-2, PSD-95, chapsyn-110, ERBIN, MALS-1, densin-180, syntrophins α1, β2, γ2, MUPP1, and PDZK1. After determining these binding partners, we analyzed the database of known and predicted protein interactions to obtain an NBCn1 interaction network. The network shows NBCn1 being physically and functionally associated with a variety of membrane and cytosolic proteins via the binding partners. We then focused on syntrophin γ2 to examine the molecular and functional interaction between NBCn1 and one of the identified binding partners in the Xenopus oocyte expression system. GST/NBCn1 pulled down syntrophin γ2 and conversely GST/syntrophin γ2 pulled down NBCn1. Moreover, syntrophin γ2 increased intracellular pH recovery, from acidification, mediated by NBCn1's Na/HCO3 cotransport. Syntrophin γ2 also increased an ionic conductance produced by NBCn1 channel-like activity. Thus, syntrophin γ2 regulates NBCn1 activity. In conclusion, this study demonstrates that NBCn1 binds to many PDZ proteins, which in turn may allow the transporter to associate with other physiologically important proteins.
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Affiliation(s)
- Hye Jeong Lee
- Department of Pediatrics, Division of Hematology and Oncology, Vanderbilt University, Nashville, Tennessee, USA
| | - Min Hyung Kwon
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Soojung Lee
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Randy A Hall
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - C Chris Yun
- Department of Medicine, Division of Digestive Disease, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Inyeong Choi
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia, USA
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