This proposal is to study the molecular properties and location of the """"""""aquaporin"""""""" and """"""""connexin"""""""" channels in the lens. Lens aquaporin channels (AQP1 and MIP) mediate and regulate water permeability, a critical component of the hypothesized lens internal circulatory system. Lens connexin channels (Cx43, Cx46 and Cx50) are hypothesized to conduct and direct this circulation to be inward at the anterior and posterior poles and outward at the equator. This proposal aims to locate these channels in different regions of the lens, to quantify their density and to determine how changes due to aging and some naturally occurring mutations can lead to cataract formation. To identify the proteins, this proposal will use freeze fracture label electron microscopy. To study their functional properties, expression in Xenopus laevis oocytes will be used to allow measurements of molecular properties, electrolyte and nonelectrolyte fluxes and water permeability.

National Institute of Health (NIH)
National Eye Institute (NEI)
Research Project (R01)
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Visual Sciences A Study Section (VISA)
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University of California Los Angeles
Schools of Medicine
Los Angeles
United States
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Zampighi, Guido A; Serrano, Raul; Vergara, Julio L (2014) A novel synaptic vesicle fusion path in the rat cerebral cortex: the ""saddle"" point hypothesis. PLoS One 9:e100710
Souda, Puneet; Ryan, Christopher M; Cramer, William A et al. (2011) Profiling of integral membrane proteins and their post translational modifications using high-resolution mass spectrometry. Methods 55:330-6
Schietroma, C; Fain, N; Zampighi, L M et al. (2009) The structure of the cytoplasm of lens fibers as determined by conical tomography. Exp Eye Res 88:566-74
Zampighi, Guido A; Fain, Nick; Zampighi, Lorenzo M et al. (2008) Conical electron tomography of a chemical synapse: polyhedral cages dock vesicles to the active zone. J Neurosci 28:4151-60
Salvi, Eleonora; Cantele, Francesca; Zampighi, Lorenzo et al. (2008) JUST (Java User Segmentation Tool) for semi-automatic segmentation of tomographic maps. J Struct Biol 161:287-97
Cantele, Francesca; Zampighi, Lorenzo; Radermacher, Michael et al. (2007) Local refinement: an attempt to correct for shrinkage and distortion in electron tomography. J Struct Biol 158:59-70
Zampighi, G A; Zampighi, L M; Fain, N et al. (2006) Conical electron tomography of a chemical synapse: vesicles docked to the active zone are hemi-fused. Biophys J 91:2910-8
Lin, Dingbo; Barnett, Micheal; Lobell, Samuel et al. (2006) PKCgamma knockout mouse lenses are more susceptible to oxidative stress damage. J Exp Biol 209:4371-8
Hegde, Balachandra G; Isas, J Mario; Zampighi, Guido et al. (2006) A novel calcium-independent peripheral membrane-bound form of annexin B12. Biochemistry 45:934-42
Zampighi, Guido A (2003) Distribution of connexin50 channels and hemichannels in lens fibers: a structural approach. Cell Commun Adhes 10:265-70

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