Cataract-associated D3Y mutation of human connexin46 (hCx46) increases the dye coupling of gap junction channels and suppresses the voltage sensitivity of hemichannels

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  • Center for Systems Neuroscience Hannover (ZSN)
  • Friedrich Schiller University Jena
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Details

Original languageEnglish
Pages (from-to)607-614
Number of pages8
JournalJournal of Bioenergetics and Biomembranes
Volume44
Issue number5
Publication statusPublished - 29 Jul 2012

Abstract

Connexin46 (Cx46), together with Cx50, forms gap junction channels between lens fibers and participates in the lens pump-leak system, which is essential for the homeostasis of this avascular organ. Mutations in Cx50 and Cx46 correlate with cataracts, but the functional relationship between the mutations and cataract formation is not always clear. Recently, it was found that a mutation at the third position of hCx46 that substituted an aspartic acid residue with a tyrosine residue (hCx46D3Y) caused an autosomal dominant zonular pulverulent cataract. We expressed EGFP-labeled hCx46wt and hCx46D3Y in HeLa cells and found that the mutation did not affect the formation of gap junction plaques. Dye transfer experiments using Lucifer Yellow (LY) and ethidium bromide (EthBr) showed an increased degree of dye coupling between the cell pairs expressing hCx46D3Y in comparison to the cell pairs expressing hCx46wt. In Xenopus oocytes, two-electrode voltageclamp experiments revealed that hCx46wt formed voltagesensitive hemichannels. This was not observed in the oocytes expressing hCx46D3Y. The replacement of the aspartic acid residue at the third position by another negatively charged residue, glutamic acid, to generate the mutant hCx46D3E, restored the voltage sensitivity of the resultant hemichannels. Moreover, HeLa cell pairs expressing hCx46D3E and hCx46wt showed a similar degree of dye coupling. These results indicate that the negatively charged aspartic acid residue at the third position of the N-terminus of hCx46 could be involved in the determination of the degree of metabolite cell-to-cell coupling and is essential for the voltage sensitivity of the hCx46 hemichannels.

Keywords

    Cataract, Dye transfer, HCx46, Hemichannels, N-terminus, Voltage sensitivity

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Physiology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Cell Biology

Cite this

Cataract-associated D3Y mutation of human connexin46 (hCx46) increases the dye coupling of gap junction channels and suppresses the voltage sensitivity of hemichannels. / Schlingmann, Barbara; Schadzek, Patrik; Busko, Stefan et al.
In: Journal of Bioenergetics and Biomembranes, Vol. 44, No. 5, 29.07.2012, p. 607-614.

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title = "Cataract-associated D3Y mutation of human connexin46 (hCx46) increases the dye coupling of gap junction channels and suppresses the voltage sensitivity of hemichannels",
abstract = "Connexin46 (Cx46), together with Cx50, forms gap junction channels between lens fibers and participates in the lens pump-leak system, which is essential for the homeostasis of this avascular organ. Mutations in Cx50 and Cx46 correlate with cataracts, but the functional relationship between the mutations and cataract formation is not always clear. Recently, it was found that a mutation at the third position of hCx46 that substituted an aspartic acid residue with a tyrosine residue (hCx46D3Y) caused an autosomal dominant zonular pulverulent cataract. We expressed EGFP-labeled hCx46wt and hCx46D3Y in HeLa cells and found that the mutation did not affect the formation of gap junction plaques. Dye transfer experiments using Lucifer Yellow (LY) and ethidium bromide (EthBr) showed an increased degree of dye coupling between the cell pairs expressing hCx46D3Y in comparison to the cell pairs expressing hCx46wt. In Xenopus oocytes, two-electrode voltageclamp experiments revealed that hCx46wt formed voltagesensitive hemichannels. This was not observed in the oocytes expressing hCx46D3Y. The replacement of the aspartic acid residue at the third position by another negatively charged residue, glutamic acid, to generate the mutant hCx46D3E, restored the voltage sensitivity of the resultant hemichannels. Moreover, HeLa cell pairs expressing hCx46D3E and hCx46wt showed a similar degree of dye coupling. These results indicate that the negatively charged aspartic acid residue at the third position of the N-terminus of hCx46 could be involved in the determination of the degree of metabolite cell-to-cell coupling and is essential for the voltage sensitivity of the hCx46 hemichannels.",
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TY - JOUR

T1 - Cataract-associated D3Y mutation of human connexin46 (hCx46) increases the dye coupling of gap junction channels and suppresses the voltage sensitivity of hemichannels

AU - Schlingmann, Barbara

AU - Schadzek, Patrik

AU - Busko, Stefan

AU - Heisterkamp, Alexander

AU - Ngezahayo, Anaclet

PY - 2012/7/29

Y1 - 2012/7/29

N2 - Connexin46 (Cx46), together with Cx50, forms gap junction channels between lens fibers and participates in the lens pump-leak system, which is essential for the homeostasis of this avascular organ. Mutations in Cx50 and Cx46 correlate with cataracts, but the functional relationship between the mutations and cataract formation is not always clear. Recently, it was found that a mutation at the third position of hCx46 that substituted an aspartic acid residue with a tyrosine residue (hCx46D3Y) caused an autosomal dominant zonular pulverulent cataract. We expressed EGFP-labeled hCx46wt and hCx46D3Y in HeLa cells and found that the mutation did not affect the formation of gap junction plaques. Dye transfer experiments using Lucifer Yellow (LY) and ethidium bromide (EthBr) showed an increased degree of dye coupling between the cell pairs expressing hCx46D3Y in comparison to the cell pairs expressing hCx46wt. In Xenopus oocytes, two-electrode voltageclamp experiments revealed that hCx46wt formed voltagesensitive hemichannels. This was not observed in the oocytes expressing hCx46D3Y. The replacement of the aspartic acid residue at the third position by another negatively charged residue, glutamic acid, to generate the mutant hCx46D3E, restored the voltage sensitivity of the resultant hemichannels. Moreover, HeLa cell pairs expressing hCx46D3E and hCx46wt showed a similar degree of dye coupling. These results indicate that the negatively charged aspartic acid residue at the third position of the N-terminus of hCx46 could be involved in the determination of the degree of metabolite cell-to-cell coupling and is essential for the voltage sensitivity of the hCx46 hemichannels.

AB - Connexin46 (Cx46), together with Cx50, forms gap junction channels between lens fibers and participates in the lens pump-leak system, which is essential for the homeostasis of this avascular organ. Mutations in Cx50 and Cx46 correlate with cataracts, but the functional relationship between the mutations and cataract formation is not always clear. Recently, it was found that a mutation at the third position of hCx46 that substituted an aspartic acid residue with a tyrosine residue (hCx46D3Y) caused an autosomal dominant zonular pulverulent cataract. We expressed EGFP-labeled hCx46wt and hCx46D3Y in HeLa cells and found that the mutation did not affect the formation of gap junction plaques. Dye transfer experiments using Lucifer Yellow (LY) and ethidium bromide (EthBr) showed an increased degree of dye coupling between the cell pairs expressing hCx46D3Y in comparison to the cell pairs expressing hCx46wt. In Xenopus oocytes, two-electrode voltageclamp experiments revealed that hCx46wt formed voltagesensitive hemichannels. This was not observed in the oocytes expressing hCx46D3Y. The replacement of the aspartic acid residue at the third position by another negatively charged residue, glutamic acid, to generate the mutant hCx46D3E, restored the voltage sensitivity of the resultant hemichannels. Moreover, HeLa cell pairs expressing hCx46D3E and hCx46wt showed a similar degree of dye coupling. These results indicate that the negatively charged aspartic acid residue at the third position of the N-terminus of hCx46 could be involved in the determination of the degree of metabolite cell-to-cell coupling and is essential for the voltage sensitivity of the hCx46 hemichannels.

KW - Cataract

KW - Dye transfer

KW - HCx46

KW - Hemichannels

KW - N-terminus

KW - Voltage sensitivity

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U2 - 10.1007/s10863-012-9461-0

DO - 10.1007/s10863-012-9461-0

M3 - Article

C2 - 22843197

AN - SCOPUS:84866729303

VL - 44

SP - 607

EP - 614

JO - Journal of Bioenergetics and Biomembranes

JF - Journal of Bioenergetics and Biomembranes

SN - 0145-479X

IS - 5

ER -

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