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Yang W, Jo SH, Lee TW. Perovskite Colloidal Nanocrystal Solar Cells: Current Advances, Challenges, and Future Perspectives. Adv Mater 2024:e2401788. [PMID: 38708900 DOI: 10.1002/adma.202401788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/06/2024] [Indexed: 05/07/2024]
Abstract
The power conversion efficiencies (PCEs) of polycrystalline perovskite (PVK) solar cells (SCs) (PC-PeSCs) have rapidly increased. However, PC-PeSCs are intrinsically unstable without encapsulation, and their efficiency drops during large-scale production; these problems hinder the commercial viability of PeSCs. Stability can be increased by using colloidal PVK nanocrystals (c-PeNCs), which have high surface strains, low defect density, and exceptional crystal quality. The use of c-PeNCs separates the crystallization process from the film formation process, which is preponderant in large-scale fabrication. Consequently, the use of c-PeNCs has substantial potential to overcome challenges encountered when fabricating PC-PeSCs. Research on colloidal nanocrystal-based PVK SCs (NC-PeSCs) has increased their PCEs to a level greater than those of other quantum-dot SCs, but has not reached the PCEs of PC-PeSCs; this inferiority significantly impedes widespread application of NC-PeSCs. This review first introduces the distinctive properties of c-PeNCs, then the strategies that have been used to achieve high-efficiency NC-PeSCs. Then it discusses in detail the persisting challenges in this domain. Specifically, the major challenges and solutions for NC-PeSCs related to low short-circuit current density Jsc are covered. Last, the article presents a perspective on future research directions and potential applications in the realm of NC-PeSCs.
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Affiliation(s)
- Wenqiang Yang
- Institute of Atomic Manufacturing, International Research Institute for Multidisciplinary Science, Beihang University, Beijing, 100191, China
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Seung-Hyeon Jo
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Tae-Woo Lee
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- Research Institute of Advanced Materials, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- Interdisciplinary program in Bioengineering, Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- Soft Foundry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
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Yang W, Jo SH, Tang Y, Park J, Ji SG, Cho SH, Hong Y, Kim DH, Park J, Yoon E, Zhou H, Woo SJ, Kim H, Yun HJ, Lee YS, Kim JY, Hu B, Lee TW. Overcoming Charge Confinement in Perovskite Nanocrystal Solar Cells. Adv Mater 2023; 35:e2304533. [PMID: 37390092 DOI: 10.1002/adma.202304533] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/02/2023]
Abstract
The small nanoparticle size and long-chain ligands in colloidal metal halide perovskite quantum dots (PeQDs) cause charge confinement, which impedes exciton dissociation and carrier extraction in PeQD solar cells, so they have low short-circuit current density Jsc , which impedes further increases in their power conversion efficiency (PCE). Here, a re-assembling process (RP) is developed for perovskite nanocrystalline (PeNC) films made of colloidal perovskite nanocrystals to increase Jsc in PeNC solar cells. The RP of PeNC films increases their crystallite size and eliminates long-chain ligands, and thereby overcomes the charge confinement in PeNC films. These changes facilitate exciton dissociation and increase carrier extraction in PeNC solar cells. By use of this method, the gradient-bandgap PeNC solar cells achieve a Jsc = 19.30 mA cm-2 without compromising the photovoltage, and yield a high PCE of 16.46% with negligible hysteresis and good stability. This work provides a new strategy to process PeNC films and pave the way for high performance PeNC optoelectronic devices.
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Affiliation(s)
- Wenqiang Yang
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- Research Institute of Advanced Materials, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Seung-Hyeon Jo
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Yipeng Tang
- Department of Materials Science and Engineering, University of Tennessee, 1001-1099 Estabrook Rd, Knoxville, TN, 37996, USA
| | - Jumi Park
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemoon-gu, Seoul, 03722, Republic of Korea
| | - Su Geun Ji
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Seong Ho Cho
- Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Yongseok Hong
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemoon-gu, Seoul, 03722, Republic of Korea
| | - Dong-Hyeok Kim
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Jinwoo Park
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Eojin Yoon
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Huanyu Zhou
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Seung-Je Woo
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Hyeran Kim
- Advanced Nano Research Group, Korea Basic Science Institute (KBSI), 169-148 Gwahak-ro, Yuseong-gu, Daejeon, 34126, Republic of Korea
| | - Hyung Joong Yun
- Advanced Nano Research Group, Korea Basic Science Institute (KBSI), 169-148 Gwahak-ro, Yuseong-gu, Daejeon, 34126, Republic of Korea
| | - Yun Seog Lee
- Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Jin Young Kim
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Bin Hu
- Department of Materials Science and Engineering, University of Tennessee, 1001-1099 Estabrook Rd, Knoxville, TN, 37996, USA
| | - Tae-Woo Lee
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- Research Institute of Advanced Materials, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- SN Display Co. Ltd., 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- School of Chemical and Biological Engineering, Institute of Engineering Research, Soft Foundry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
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Jeon YJ, Han YJ, Choi MH, Lee JS, Lee JH, Jo SH, Kim SH. Mental health states and influencing factors of risky and problem drinking in South Korean female adolescents. Public Health 2020; 185:61-69. [PMID: 32570147 DOI: 10.1016/j.puhe.2020.04.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/12/2020] [Accepted: 04/21/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Alcohol is one of the most used and abused psychoactive substances by adolescents. We investigated influencing factors of risky and problem drinking in Korean female adolescents. STUDY DESIGN The study design used is a cross-sectional modeling. METHODS We used data from the 13th Korean Youth Risk Behavior Web-based Survey (KYRBS) conducted in 2017. KYRBS data were obtained from a stratified, multistage, clustered sample. Risky drinking was binge drinking and problem drinking was drinking with several conflicts association with alcohol consumption. RESULTS Among 62,276 participants, the rates of current, risky, and problem drinking among all participants were 16.1%, 8.3%, and 6.1%, respectively. Although all of these rates were higher in males, risky and problem drinking rates among current female drinkers were higher than those of males (55.4 vs 48.5%, 38.9 vs 37.2%, respectively). Problem drinking was most strongly associated with risky drinking (adjusted odds ratio: 17.53 [95% confidence interval: 14.63-21.00]), similarly, risky drinking was most strongly associated with problem drinking in female current drinkers (17.76 [14.84-21.27]). Current smoking was the second strongest risk factor for risky and problem drinking in females (5.22 [3.92-6.95] and 2.93 [2.21-3.89], respectively). CONCLUSION Many female adolescents in Korea drink alcohol in an unhealthy manner. The female risky and problem drinking rates among current drinkers were higher than those of males. Risky drinking and problem drinking was most significant influencing factor among females, reciprocally. Public education on abstinence in female adolescents is warranted.
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Affiliation(s)
- Y J Jeon
- Department of Pediatrics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea
| | - Y J Han
- Department of Pediatrics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea
| | - M H Choi
- Department of Pediatrics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea
| | - J S Lee
- Department of Pediatrics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea
| | - J H Lee
- Department of Pediatrics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea
| | - S H Jo
- Department of Biostatstics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea
| | - S H Kim
- Department of Pediatrics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea.
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Jo SH, Kim S, Kim HD, Jeong B, Lee H. Local structural change and catalytic activity of Zr-doped amorphous CeTiOx for the low-temperature selective catalytic reduction of NO with NH3. Reac Kinet Mech Cat 2018. [DOI: 10.1007/s11144-018-1464-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Hwang S, Jo SH, Kim J, Shin MC, Chun HH, Park H, Lee H. Catalytic activity of MnOx/TiO2 catalysts synthesized with different manganese precursors for the selective catalytic reduction of nitrogen oxides. Reac Kinet Mech Cat 2015. [DOI: 10.1007/s11144-015-0948-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kim MY, Jo SH, Park JM, Kim TH, Im SS, Ahn YH. Adenovirus-mediated overexpression of Tcfe3 ameliorates hyperglycaemia in a mouse model of diabetes by upregulating glucokinase in the liver. Diabetologia 2013; 56:635-43. [PMID: 23269357 DOI: 10.1007/s00125-012-2807-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 12/04/2012] [Indexed: 11/30/2022]
Abstract
AIMS/HYPOTHESIS Transcription factor E3 (TFE3) has been shown to increase insulin sensitivity by activating insulin-signalling pathways. However, the role of TFE3 in glucose homeostasis is not fully understood. Here, we explored the possible therapeutic potential of TFE3 for the control of hyperglycaemia using a streptozotocin-induced mouse model of diabetes. METHODS We achieved overabundance of TFE3 in streptozotocin mice by administering an adenovirus (Ad) or adeno-associated virus serotype 2 (AAV2). We also performed an oral glucose tolerance test (OGTT) and insulin tolerance test (ITT). To explore molecular mechanisms of blood glucose control by TFE3, transcriptional studies on the regulation of genes involved in hepatic glucose metabolism were performed using quantitative real-time PCR and chromatin immunoprecipitation assay. The binding site of TFE3 in the liver Gck gene promoter was identified using deletion and site-specific mutation studies. RESULTS Overabundance of TFE3 resulted in reduced hyperglycaemia as shown by the OGTT and ITT in streptozotocin-treated mice. We observed that TFE3 can upregulate Gck in a state of insulin deficiency. However, glucose-6-phosphatase and cytosolic phosphoenolpyruvate carboxykinase mRNA levels were decreased by Ad-mediated overexpression of Tcfe3. Biochemical studies revealed that the anti-hyperglycaemic effect of TFE3 is due to the upregulation of Gck. In primary cultured hepatocytes, TFE3 increased expression of Gck mRNA. Conversely, small interfering RNA-mediated knockdown of TFE3 resulted in a decrease in Gck mRNA. CONCLUSIONS/INTERPRETATION This study demonstrates that TFE3 counteracts hyperglycaemia in streptozotocin-treated mice. This effect could be due to the upregulation of Gck by binding of TFE3 to its cognitive promoter region.
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Affiliation(s)
- M Y Kim
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Republic of Korea
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Abstract
The theoretical maximum tensile strain--that is, elongation--of a single-walled carbon nanotube is almost 20%, but in practice only 6% is achieved. Here we show that, at high temperatures, individual single-walled carbon nanotubes can undergo superplastic deformation, becoming nearly 280% longer and 15 times narrower before breaking. This superplastic deformation is the result of the nucleation and motion of kinks in the structure, and could prove useful in helping to strengthen and toughen ceramics and other nanocomposites at high temperatures.
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Affiliation(s)
- J Y Huang
- Department of Physics, Boston College, Boston, Massachusetts 02467, USA.
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Huang JY, Chen S, Jo SH, Wang Z, Han DX, Chen G, Dresselhaus MS, Ren ZF. Atomic-scale imaging of wall-by-wall breakdown and concurrent transport measurements in multiwall carbon nanotubes. Phys Rev Lett 2005; 94:236802. [PMID: 16090493 DOI: 10.1103/physrevlett.94.236802] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Indexed: 05/03/2023]
Abstract
We report the atomic-scale imaging with concurrent transport measurements of the breakdown of individual multiwall carbon nanotubes inside a transmission electron microscope equipped with a piezomanipulator. We found unexpectedly three distinct breakdown sequences: namely, from the outermost wall inward, from the innermost wall outward, and alternatively between the innermost and the outmost walls. Remarkably, a significant amount of current drop was observed when an innermost wall is broken, proving unambiguously that every wall is conducting. Moreover, the breakdown of each wall in any sequence initiates in the middle of the nanotube, not at the contact, proving that the transport is not ballistic.
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Affiliation(s)
- J Y Huang
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA.
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Lee SH, Jo SH, Lee SM, Koh HJ, Song H, Park JW, Lee WH, Huh TL. Role of NADP+-dependent isocitrate dehydrogenase (NADP+-ICDH) on cellular defence against oxidative injury by gamma-rays. Int J Radiat Biol 2005; 80:635-42. [PMID: 15586883 DOI: 10.1080/09553000400007680] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
PURPOSE To investigate the regulation of NADPH-producing isocitrate dehydrogenase (ICDH) in cytosol (IDPc) and mitochondria (IDPm) upon gamma-ray irradiation, and the roles of IDPc and IDPm in the protection against cellular damage induced by gamma-ray irradiation. MATERIALS AND METHODS Changes of IDPc and IDPm proteins upon gamma-ray irradiation to NIH3T3 cells were analysed by immunoblotting. To increase or decrease the expression of IDPc or IDPm, NIH3T3 cells were stably transfected with mouse IDPc or IDPm cDNA in either the sense or the antisense direction. The transfected cells with either increased or decreased IDPc or IDPm were exposed to gamma-rays, and the levels of reactive oxygen species generation, protein oxidation and lipid peroxidation were measured. RESULTS Both IDPc and IDPm activities were induced by gamma-ray in NIH3T3 cells. Cells with decreased expression of IDPc or IDPm had elevated reactive oxygen species generation, lipid peroxidation and protein oxidation. Conversely, overproduction of IDPc or IDPm protein partially protected the cells from oxidative damage induced by gamma-ray irradiation. CONCLUSIONS The protective role of IDPc and IDPm against gamma-ray-induced cellular damage can be attributed to elevated NADPH, reducing equivalents needed for recycling reduced glutathione in the cytosol and mitochondria. Thus, a primary biological function of the ICDHs may be production of NADPH, which is a prerequisite for some cellular defence systems against oxidative damage.
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Affiliation(s)
- S H Lee
- Department of Genetic Engineering, Kyungpook National University, Daegu 702-701, Korea
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Jo SH, Choi SY, Kim KT, Lee CO. Effects of polychlorinated biphenyl 19 (2,2',6-trichlorobiphenyl) on contraction, Ca2+ transient, and Ca2+ current of cardiac myocytes. J Cardiovasc Pharmacol 2001; 38:11-20. [PMID: 11444494 DOI: 10.1097/00005344-200107000-00002] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Polychlorinated biphenyls (PCBs) have been known as serious environmental pollutants, causing developmental delays, motor dysfunction, and decrease in brain dopamine level in humans and animals. We have investigated the effects of a PCB congener, 2,2',6-trichlorobiphenyl (PCB 19) on contractile force, Ca2+ transient, and L-type Ca2+ current (I(Ca,L)) in guinea pig ventricular myocytes stimulated at a rate of 0.25-0.33 Hz. PCB 19 decreased contractile force in a concentration-dependent manner. During the negative inotropic response, the action potential duration at 20% (APD20), 90% of repolarization (APD90), and the action potential amplitude (APA) were decreased concentration dependently: 30 microM PCB 19 reduced APD20, APD90 and APA by 36.7 +/- 3.5%, 22.6 +/- 3.9%, and 2.4 +/- 0.6%, respectively (n = 11, p < 0.01). PCB 19 30 microM decreased the Ca2+ transient and the I(Ca,L) by 46.8 +/- 1.8% (n = 9, p < 0.01) and 47.1 +/- 3.1% (n = 9, p < 0.01), respectively. The results suggest that PCB 19 decreased the Ca2+ transient through inhibition of L-type Ca2+ channels and that the decreased Ca2+ transient consequently caused a negative inotropic effect in cardiac myocytes.
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Affiliation(s)
- S H Jo
- Department of Life Science, Pohang University of Science and Technology, Republic of Korea
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Jo SH, Son MK, Koh HJ, Lee SM, Song IH, Kim YO, Lee YS, Jeong KS, Kim WB, Park JW, Song BJ, Huh TL, Huhe TL. Control of mitochondrial redox balance and cellular defense against oxidative damage by mitochondrial NADP+-dependent isocitrate dehydrogenase. J Biol Chem 2001; 276:16168-76. [PMID: 11278619 DOI: 10.1074/jbc.m010120200] [Citation(s) in RCA: 398] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitochondria are the major organelles that produce reactive oxygen species (ROS) and the main target of ROS-induced damage as observed in various pathological states including aging. Production of NADPH required for the regeneration of glutathione in the mitochondria is critical for scavenging mitochondrial ROS through glutathione reductase and peroxidase systems. We investigated the role of mitochondrial NADP(+)-dependent isocitrate dehydrogenase (IDPm) in controlling the mitochondrial redox balance and subsequent cellular defense against oxidative damage. We demonstrate in this report that IDPm is induced by ROS and that decreased expression of IDPm markedly elevates the ROS generation, DNA fragmentation, lipid peroxidation, and concurrent mitochondrial damage with a significant reduction in ATP level. Conversely, overproduction of IDPm protein efficiently protected the cells from ROS-induced damage. The protective role of IDPm against oxidative damage may be attributed to increased levels of a reducing equivalent, NADPH, needed for regeneration of glutathione in the mitochondria. Our results strongly indicate that IDPm is a major NADPH producer in the mitochondria and thus plays a key role in cellular defense against oxidative stress-induced damage.
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Affiliation(s)
- S H Jo
- Departments of Genetic Engineering and Biochemistry, Kyungpook National University, Taegu 702-701, Korea
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Abstract
We investigated the role of protein kinase C (PKC) in alpha(1)-adrenergic regulation of intracellular Na(+) activity (a(Na)(i)) in single guinea pig ventricular myocytes. a(Na)(i) and membrane potentials were measured with the Na(+)-sensitive indicator sodium-binding benzofuran isophthalate and conventional microelectrodes, respectively, at room temperature (24-26 degrees C) while myocytes were stimulated at a rate of 0.25-0.3 Hz. The PKC activator 4beta-phorbol 12-myristate 13-acetate (PMA) decreased a(Na)(i) in a concentration-dependent manner. PMA (100 nM) produced a maximal decrease in a(Na)(i) of 1.5 mM from 6.5 +/- 0.4 to 5.0 +/- 0.4 mM (means +/- SE, n = 12, P < 0.01). The PMA concentration required for a half-maximal decrease in a(Na)(i) was 0.46 +/- 0.13 nM (n = 3, P < 0.01). An inactive phorbol, 4alpha-phorbol 12-myristate 13-acetate, did not decrease a(Na)(i). The decrease caused by PMA could be blocked by the PKC inhibitors staurosporine and bisindolylmaleimide I (GF-109203X). Stimulation of the alpha(1)-adrenoceptor with 50 microM phenylephrine decreased a(Na)(i) from 6.1 +/- 0.3 to 4.6 +/- 0.3 mM (n = 11, P < 0.01). The decrease in a(Na)(i) produced by phenylephrine was blocked by pretreatment with staurosporine, GF-109203X, or PMA. The decrease in a(Na)(i) produced by PMA was not prevented by pretreatment with tetrodotoxin but was blocked by pretreatment with strophanthidin or high extracellular K(+) concentration. The results suggest that alpha(1)-adrenergic receptor activation results in a decrease in a(Na)(i) via PKC-induced stimulation of the Na(+)-K(+) pump in cardiac myocytes.
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Affiliation(s)
- S H Jo
- Department of Life Science, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
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Kim YO, Koh HJ, Kim SH, Jo SH, Huh JW, Jeong KS, Lee IJ, Song BJ, Huh TL. Identification and functional characterization of a novel, tissue-specific NAD(+)-dependent isocitrate dehydrogenase beta subunit isoform. J Biol Chem 1999; 274:36866-75. [PMID: 10601238 DOI: 10.1074/jbc.274.52.36866] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To understand the interactions and functional role of each of the three mitochondrial NAD(+)-dependent isocitrate dehydrogenase (IDH) subunits (alpha, beta, and gamma), we have characterized human cDNAs encoding two beta isoforms (beta(1) and beta(2)) and the gamma subunit. Analysis of deduced amino acid sequences revealed that beta(1) and beta(2) encode 349 and 354 amino acids, respectively, and the two isoforms only differ in the most carboxyl 28 amino acids. The gamma cDNA encodes 354 amino acids and is almost identical to monkey IDHgamma. Northern analyses revealed that the smaller beta(2) transcript (1.3 kilobases) is primarily expressed in heart and skeletal muscle, whereas the larger beta(1) mRNA (1.6 kilobases) is prevalent in nonmuscle tissues. Sequence analysis of the IDHbeta gene indicates that the difference in the C-terminal 28 amino acids between beta(1) and beta(2) proteins results from alternative splicing of a single transcript. Among the various combinations of human IDH subunits co-expressed in bacteria, alphabetagamma, alphabeta, and alphagamma combinations exhibited significant amounts of IDH activity, whereas subunits produced alone and betagamma showed no detectable activity. These data suggest that the alpha is the catalytic subunit and that at least one of the other two subunits plays an essential supporting role for activity. Substitution of beta(1) with beta(2) in the co-expression system lowered the pH optimum for IDH activity from 8.0 to 7.6. This difference in optimal pH was analogous to what was observed in mouse kidney and brain (beta(1) prevalent; optimal pH 8.0) versus heart (beta(2) prevalent; pH 7.6) mitochondria. Experiments with a specially designed splicing reporter construct stably transfected into HT1080 cells indicate that acidic conditions favor a splicing pattern responsible for the muscle- and heart-specific beta(2) isoform. Taken together, these data indicate a regulatory role of IDHbeta isoforms in determining the pH optimum for IDH activity through the tissue-specific alternative splicing.
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Affiliation(s)
- Y O Kim
- Department of Genetic Engineering, College of Natural Sciences, Kyungpook National University, Taegu 702-701, Korea
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Abstract
We have investigated the effect of external H+ concentration ([H+]o) on the human-ether-a-go-go-related gene (HERG) current (IHERG), the molecular equivalent of the cardiac delayed rectifier potassium current (IKr), expressed in Xenopus oocytes, using the two-microelectrode voltage-clamp technique. When [H+]o was increased, the amplitude of the IHERG elicited by depolarization decreased, and the rate of current decay on repolarization was accelerated. The activation curve shifted to a more positive potential at lower external pH (pHo) values (the potential required for half-maximum activation, V1/2, was: -41.8 mV, -38.0 mV, -33.7 mV, -26.7 mV in pHo 8.0, 7.0, 6.6, 6.2, respectively). The maximum conductance (gmax) was also affected by [H+]o: a reduction of 7.9%, 14.6%, and 22.8% was effected by decreasing pHo from 8.0 to 7.0, 6.6, and 6.2, respectively. We then tested whether this pH effect was affected by the external Ca2+ concentration, which is also known to block HERG channels. When the extracellular Ca2+ concentration was increased from 0.5 mM to 5 mM, the shift in V1/2 caused by increasing [H+]o was attenuated, suggesting that these two ions compete for the same binding site. On the other hand, the decrease in gmax caused by increasing [H+]o was not significantly affected by changing external Ca2+ levels. The results indicate that HERG channels are inhibited by [H+]o by two different mechanisms: voltage-dependent blockade (shift of V1/2) and the decrease in gmax. With respect to the voltage-dependent blockade, the interaction between H+ and Ca2+ is competitive, whereas for the decreasing gmax, their interaction is non-competitive.
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Affiliation(s)
- S H Jo
- Department of Life Science, Pohang University of Science and Technology, Pohang 790-784, South Korea
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