Abstract
Purpose :
To determine the potential involvement of Periaxin (Prx), a PDZ domain containing protein, in regulation of N-cadherin/Catenin-based cell adhesive interactions in lens fibers.
Methods :
Immunoprecipitation in conjunction with mass spectrometry and immunoblot analysis of lens homogenates was performed to assess the interaction of catenins with Prx and Ankyrin-B (AnkB) in lens tissue. The expression, distribution and colocalization of αN-catenin with different cell adhesion, cytoskeletal and membrane proteins in mouse lens tissue was determined either by cDNA microarray, immunoblot or immunofluorescence analyses. The integrity of N-cadherin and αN-catenin-based cell adhesive interactions in the absence of Prx was determined using Prx null mouse lenses.
Results :
αN-catenin is expressed in a lens fiber-specific manner in both embryonic and adult mouse lenses, and distributes to both, the soluble and the membrane fractions. This neuronal subtype catenin exhibits a maturation-dependent increase in expression in mouse lenses and coimmunoprecipitates with Prx and AnkB from lens homogenates. αN-catenin coexists with N-cadherin, β-catenin, Prx and AnkB in the lens fiber cell membrane rafts as determined by proteomics analysis of lipid rafts derived from the porcine lens, and colocalizes with N-cadherin, Prx, AnkB, Actin and NrCAM in the mouse lens fibers. Importantly, in the Prx null mouse lens, αN-catenin accumulates in the soluble fraction with a concomitant reduction in the membrane fraction.
Conclusions :
These results demonstrate that αN-catenin exhibits a lens fiber-specific pattern of expression and colocalizes with N-cadherin, Prx, Actin and AnkB. The coimmunoprecipitation of αN-catenin with Prx and AnkB, in coexistence of αN-catenin with N-cadherin, β-catenin, Prx and AnkB in membrane rafts , and impairment of αN-catenin membrane localization in the absence of Prx in lens fibers, collectively suggests a crucial role for Prx in formation and stabilization of N-cadherin/αN-catenin-based cell adhesive interactions.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.