Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 607-614 |
| Seitenumfang | 8 |
| Fachzeitschrift | Journal of Bioenergetics and Biomembranes |
| Jahrgang | 44 |
| Ausgabenummer | 5 |
| Publikationsstatus | Veröffentlicht - 29 Juli 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.
ASJC Scopus Sachgebiete
- Biochemie, Genetik und Molekularbiologie (insg.)
- Physiologie
- Biochemie, Genetik und Molekularbiologie (insg.)
- Zellbiologie
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in: Journal of Bioenergetics and Biomembranes, Jahrgang 44, Nr. 5, 29.07.2012, S. 607-614.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
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
UR - http://www.scopus.com/inward/record.url?scp=84866729303&partnerID=8YFLogxK
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 -