Cataract-associated connexin 46 mutation alters its interaction with calmodulin and function of hemichannels [Cell Biology]
Zhengping Hu, Manuel A. Riquelme, Bin Wang, Vladislav Bugay, Robert Brenner, Sumin Gu, Jean X. Jiang
The American Society for Biochemistry and Molecular Biology (ASBMB)
Published 2018
The American Society for Biochemistry and Molecular Biology (ASBMB)
Published 2018
| Publication Date: |
2018-02-17
|
|---|---|
| Publisher: |
The American Society for Biochemistry and Molecular Biology (ASBMB)
|
| Print ISSN: |
0021-9258
|
| Electronic ISSN: |
1083-351X
|
| Topics: |
Biology
Chemistry and Pharmacology
|
| Published by: |
| _version_ | 1836398799929475073 |
|---|---|
| autor | Zhengping Hu, Manuel A. Riquelme, Bin Wang, Vladislav Bugay, Robert Brenner, Sumin Gu, Jean X. Jiang |
| beschreibung | Connexin channels help maintain eye lens homeostasis and transparency. The G143R missense substitution in connexin (Cx) 46 is associated with congenital Coppock cataracts; however, the underlying molecular mechanism is largely unknown. Here, we report that compared with WT Cx46, the G143R substitution abolishes hemichannel conductance in Xenopus oocytes and in HeLa cells. Moreover, this substitution is dominant-negative and inhibits conductance of WT Cx46. CD analysis indicated that the substitution greatly reduces the α-helical structure of the intracellular Cx46 loop domain. Protein pulldown assays and isothermal titration calorimetry revealed that this Cx46 domain directly interacts with calmodulin (CaM) in a Ca2+-dependent fashion, an observation confirmed by immunofluorescent co-localization of Cx46 with CaM. Interestingly, the G143R substitution enhanced the Cx46–CaM interaction and attenuated its abolishment by Ca2+ depletion. Moreover, Cx46 increased dye influx, and the G143R substitution augmented this effect. Inhibition of Ca2+-mediated CaM activation blocked hemichannel permeability. The membrane potential plays a crucial role in Cx46 membrane permeability. We found that the activity of hemichannels is detectable under rest and hyperpolarization conditions but is eliminated with depolarization. These results suggested that the G143R substitution impairs voltage-dependent electrical conductance and alters membrane permeability mediated by Cx46 hemichannels. The latter likely is caused by the substitution-induced structural changes of the intracellular loop domain associated with the increased interaction with CaM and reduced Ca2+ sensitivity. The data suggest that the G143R-induced enhancement of the CaM–Cx46 interaction results in altered hemichannel activities and might be related to cataract formation. |
| citation_standardnr | 6167623 |
| datenlieferant | ipn_articles |
| feed_id | 43 |
| feed_publisher | The American Society for Biochemistry and Molecular Biology (ASBMB) |
| feed_publisher_url | http://www.asbmb.org/ |
| insertion_date | 2018-02-17 |
| journaleissn | 1083-351X |
| journalissn | 0021-9258 |
| publikationsjahr_anzeige | 2018 |
| publikationsjahr_facette | 2018 |
| publikationsjahr_intervall | 7984:2015-2019 |
| publikationsjahr_sort | 2018 |
| publisher | The American Society for Biochemistry and Molecular Biology (ASBMB) |
| quelle | Journal of Biological Chemistry |
| relation | http://feedproxy.google.com/~r/jbc/SUcv/~3/kJqj6z9yyew/2573.short |
| search_space | articles |
| shingle_author_1 | Zhengping Hu, Manuel A. Riquelme, Bin Wang, Vladislav Bugay, Robert Brenner, Sumin Gu, Jean X. Jiang |
| shingle_author_2 | Zhengping Hu, Manuel A. Riquelme, Bin Wang, Vladislav Bugay, Robert Brenner, Sumin Gu, Jean X. Jiang |
| shingle_author_3 | Zhengping Hu, Manuel A. Riquelme, Bin Wang, Vladislav Bugay, Robert Brenner, Sumin Gu, Jean X. Jiang |
| shingle_author_4 | Zhengping Hu, Manuel A. Riquelme, Bin Wang, Vladislav Bugay, Robert Brenner, Sumin Gu, Jean X. Jiang |
| shingle_catch_all_1 | Cataract-associated connexin 46 mutation alters its interaction with calmodulin and function of hemichannels [Cell Biology] Connexin channels help maintain eye lens homeostasis and transparency. The G143R missense substitution in connexin (Cx) 46 is associated with congenital Coppock cataracts; however, the underlying molecular mechanism is largely unknown. Here, we report that compared with WT Cx46, the G143R substitution abolishes hemichannel conductance in Xenopus oocytes and in HeLa cells. Moreover, this substitution is dominant-negative and inhibits conductance of WT Cx46. CD analysis indicated that the substitution greatly reduces the α-helical structure of the intracellular Cx46 loop domain. Protein pulldown assays and isothermal titration calorimetry revealed that this Cx46 domain directly interacts with calmodulin (CaM) in a Ca2+-dependent fashion, an observation confirmed by immunofluorescent co-localization of Cx46 with CaM. Interestingly, the G143R substitution enhanced the Cx46–CaM interaction and attenuated its abolishment by Ca2+ depletion. Moreover, Cx46 increased dye influx, and the G143R substitution augmented this effect. Inhibition of Ca2+-mediated CaM activation blocked hemichannel permeability. The membrane potential plays a crucial role in Cx46 membrane permeability. We found that the activity of hemichannels is detectable under rest and hyperpolarization conditions but is eliminated with depolarization. These results suggested that the G143R substitution impairs voltage-dependent electrical conductance and alters membrane permeability mediated by Cx46 hemichannels. The latter likely is caused by the substitution-induced structural changes of the intracellular loop domain associated with the increased interaction with CaM and reduced Ca2+ sensitivity. The data suggest that the G143R-induced enhancement of the CaM–Cx46 interaction results in altered hemichannel activities and might be related to cataract formation. Zhengping Hu, Manuel A. Riquelme, Bin Wang, Vladislav Bugay, Robert Brenner, Sumin Gu, Jean X. Jiang The American Society for Biochemistry and Molecular Biology (ASBMB) 0021-9258 00219258 1083-351X 1083351X |
| shingle_catch_all_2 | Cataract-associated connexin 46 mutation alters its interaction with calmodulin and function of hemichannels [Cell Biology] Connexin channels help maintain eye lens homeostasis and transparency. The G143R missense substitution in connexin (Cx) 46 is associated with congenital Coppock cataracts; however, the underlying molecular mechanism is largely unknown. Here, we report that compared with WT Cx46, the G143R substitution abolishes hemichannel conductance in Xenopus oocytes and in HeLa cells. Moreover, this substitution is dominant-negative and inhibits conductance of WT Cx46. CD analysis indicated that the substitution greatly reduces the α-helical structure of the intracellular Cx46 loop domain. Protein pulldown assays and isothermal titration calorimetry revealed that this Cx46 domain directly interacts with calmodulin (CaM) in a Ca2+-dependent fashion, an observation confirmed by immunofluorescent co-localization of Cx46 with CaM. Interestingly, the G143R substitution enhanced the Cx46–CaM interaction and attenuated its abolishment by Ca2+ depletion. Moreover, Cx46 increased dye influx, and the G143R substitution augmented this effect. Inhibition of Ca2+-mediated CaM activation blocked hemichannel permeability. The membrane potential plays a crucial role in Cx46 membrane permeability. We found that the activity of hemichannels is detectable under rest and hyperpolarization conditions but is eliminated with depolarization. These results suggested that the G143R substitution impairs voltage-dependent electrical conductance and alters membrane permeability mediated by Cx46 hemichannels. The latter likely is caused by the substitution-induced structural changes of the intracellular loop domain associated with the increased interaction with CaM and reduced Ca2+ sensitivity. The data suggest that the G143R-induced enhancement of the CaM–Cx46 interaction results in altered hemichannel activities and might be related to cataract formation. Zhengping Hu, Manuel A. Riquelme, Bin Wang, Vladislav Bugay, Robert Brenner, Sumin Gu, Jean X. Jiang The American Society for Biochemistry and Molecular Biology (ASBMB) 0021-9258 00219258 1083-351X 1083351X |
| shingle_catch_all_3 | Cataract-associated connexin 46 mutation alters its interaction with calmodulin and function of hemichannels [Cell Biology] Connexin channels help maintain eye lens homeostasis and transparency. The G143R missense substitution in connexin (Cx) 46 is associated with congenital Coppock cataracts; however, the underlying molecular mechanism is largely unknown. Here, we report that compared with WT Cx46, the G143R substitution abolishes hemichannel conductance in Xenopus oocytes and in HeLa cells. Moreover, this substitution is dominant-negative and inhibits conductance of WT Cx46. CD analysis indicated that the substitution greatly reduces the α-helical structure of the intracellular Cx46 loop domain. Protein pulldown assays and isothermal titration calorimetry revealed that this Cx46 domain directly interacts with calmodulin (CaM) in a Ca2+-dependent fashion, an observation confirmed by immunofluorescent co-localization of Cx46 with CaM. Interestingly, the G143R substitution enhanced the Cx46–CaM interaction and attenuated its abolishment by Ca2+ depletion. Moreover, Cx46 increased dye influx, and the G143R substitution augmented this effect. Inhibition of Ca2+-mediated CaM activation blocked hemichannel permeability. The membrane potential plays a crucial role in Cx46 membrane permeability. We found that the activity of hemichannels is detectable under rest and hyperpolarization conditions but is eliminated with depolarization. These results suggested that the G143R substitution impairs voltage-dependent electrical conductance and alters membrane permeability mediated by Cx46 hemichannels. The latter likely is caused by the substitution-induced structural changes of the intracellular loop domain associated with the increased interaction with CaM and reduced Ca2+ sensitivity. The data suggest that the G143R-induced enhancement of the CaM–Cx46 interaction results in altered hemichannel activities and might be related to cataract formation. Zhengping Hu, Manuel A. Riquelme, Bin Wang, Vladislav Bugay, Robert Brenner, Sumin Gu, Jean X. Jiang The American Society for Biochemistry and Molecular Biology (ASBMB) 0021-9258 00219258 1083-351X 1083351X |
| shingle_catch_all_4 | Cataract-associated connexin 46 mutation alters its interaction with calmodulin and function of hemichannels [Cell Biology] Connexin channels help maintain eye lens homeostasis and transparency. The G143R missense substitution in connexin (Cx) 46 is associated with congenital Coppock cataracts; however, the underlying molecular mechanism is largely unknown. Here, we report that compared with WT Cx46, the G143R substitution abolishes hemichannel conductance in Xenopus oocytes and in HeLa cells. Moreover, this substitution is dominant-negative and inhibits conductance of WT Cx46. CD analysis indicated that the substitution greatly reduces the α-helical structure of the intracellular Cx46 loop domain. Protein pulldown assays and isothermal titration calorimetry revealed that this Cx46 domain directly interacts with calmodulin (CaM) in a Ca2+-dependent fashion, an observation confirmed by immunofluorescent co-localization of Cx46 with CaM. Interestingly, the G143R substitution enhanced the Cx46–CaM interaction and attenuated its abolishment by Ca2+ depletion. Moreover, Cx46 increased dye influx, and the G143R substitution augmented this effect. Inhibition of Ca2+-mediated CaM activation blocked hemichannel permeability. The membrane potential plays a crucial role in Cx46 membrane permeability. We found that the activity of hemichannels is detectable under rest and hyperpolarization conditions but is eliminated with depolarization. These results suggested that the G143R substitution impairs voltage-dependent electrical conductance and alters membrane permeability mediated by Cx46 hemichannels. The latter likely is caused by the substitution-induced structural changes of the intracellular loop domain associated with the increased interaction with CaM and reduced Ca2+ sensitivity. The data suggest that the G143R-induced enhancement of the CaM–Cx46 interaction results in altered hemichannel activities and might be related to cataract formation. Zhengping Hu, Manuel A. Riquelme, Bin Wang, Vladislav Bugay, Robert Brenner, Sumin Gu, Jean X. Jiang The American Society for Biochemistry and Molecular Biology (ASBMB) 0021-9258 00219258 1083-351X 1083351X |
| shingle_title_1 | Cataract-associated connexin 46 mutation alters its interaction with calmodulin and function of hemichannels [Cell Biology] |
| shingle_title_2 | Cataract-associated connexin 46 mutation alters its interaction with calmodulin and function of hemichannels [Cell Biology] |
| shingle_title_3 | Cataract-associated connexin 46 mutation alters its interaction with calmodulin and function of hemichannels [Cell Biology] |
| shingle_title_4 | Cataract-associated connexin 46 mutation alters its interaction with calmodulin and function of hemichannels [Cell Biology] |
| timestamp | 2025-06-30T23:32:49.462Z |
| titel | Cataract-associated connexin 46 mutation alters its interaction with calmodulin and function of hemichannels [Cell Biology] |
| titel_suche | Cataract-associated connexin 46 mutation alters its interaction with calmodulin and function of hemichannels [Cell Biology] |
| topic | W V |
| uid | ipn_articles_6167623 |