Unknown

Dataset Information

0

Molecular interaction and functional regulation of connexin50 gap junctions by calmodulin.


ABSTRACT: Cx50 (connexin50), a member of the ?-family of gap junction proteins expressed in the lens of the eye, has been shown to be essential for normal lens development. In the present study, we identified a CaMBD [CaM (calmodulin)-binding domain] (residues 141-166) in the intracellular loop of Cx50. Elevations in intracellular Ca2+ concentration effected a 95% decline in gj (junctional conductance) of Cx50 in N2a cells that is likely to be mediated by CaM, because inclusion of the CaM inhibitor calmidazolium prevented this Ca2+-dependent decrease in gj. The direct involvement of the Cx50 CaMBD in this Ca2+/CaM-dependent regulation was demonstrated further by the inclusion of a synthetic peptide encompassing the CaMBD in both whole-cell patch pipettes, which effectively prevented the intracellular Ca2+-dependent decline in gj. Biophysical studies using NMR and fluorescence spectroscopy reveal further that the peptide stoichiometrically binds to Ca2+/CaM with an affinity of ~5 nM. The binding of the peptide expanded the Ca2+-sensing range of CaM by increasing the Ca2+ affinity of the C-lobe of CaM, while decreasing the Ca2+ affinity of the N-lobe of CaM. Overall, these results demonstrate that the binding of Ca2+/CaM to the intracellular loop of Cx50 is critical for mediating the Ca2+-dependent inhibition of Cx50 gap junctions in the lens of the eye.

SUBMITTER: Chen Y 

PROVIDER: S-EPMC3351833 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature

altmetric image

Publications

Molecular interaction and functional regulation of connexin50 gap junctions by calmodulin.

Chen Yanyi Y   Zhou Yubin Y   Lin Xianming X   Wong Hing-Cheung HC   Xu Qin Q   Jiang Jie J   Wang Siming S   Lurtz Monica M MM   Louis Charles F CF   Veenstra Richard D RD   Yang Jenny J JJ  

The Biochemical journal 20110501 3


Cx50 (connexin50), a member of the α-family of gap junction proteins expressed in the lens of the eye, has been shown to be essential for normal lens development. In the present study, we identified a CaMBD [CaM (calmodulin)-binding domain] (residues 141-166) in the intracellular loop of Cx50. Elevations in intracellular Ca2+ concentration effected a 95% decline in gj (junctional conductance) of Cx50 in N2a cells that is likely to be mediated by CaM, because inclusion of the CaM inhibitor calmid  ...[more]

Similar Datasets

| S-EPMC2711270 | biostudies-literature
| S-EPMC3989380 | biostudies-literature
| S-EPMC6675194 | biostudies-literature
| S-EPMC4355912 | biostudies-literature
| S-EPMC3361999 | biostudies-literature
| S-EPMC1218694 | biostudies-other
| S-EPMC2869375 | biostudies-literature
| S-EPMC4893164 | biostudies-literature
| S-EPMC5698441 | biostudies-literature
| S-EPMC2880920 | biostudies-literature