Abstract
Purpose: :
We and others previously demonstrated that SNP rs10490924 within the ARMS2/LOC387715 gene at 10q26 is strongly associated with susceptibility to age-related macular degeneration and that 12 kDa ARMS2 protein is localized to the mitochondrial outer membrane (Kanda A et al. 2007 PNAS; Kanda A et al. 2008 ARVO). The goal of these studies was to gain additional insights into the function of ARMS2 and its association with AMD.
Methods: :
We performed yeast two-hybrid screening using human retina cDNA library and pulldown assay to identify ARMS2-interacting proteins. The interaction between ARMS2 and candidate proteins was validated by co-immunoprecipitaion followed by immunoblot analysis. We also produced transgenic mice expressing ARMS2 and HTRA1 in photoreceptors.
Results: :
The yeast two hybrid analysis identified translocase of outer mitochondrial membrane 40 homolog (TOMM40) among others. This interaction was confirmed by co-immunoprecipitation from transfected COS-7 cells. Knockdown of TOMM40 by specific siRNA mislocalized ARMS2. We also identified specific ARMS2-interacting heat shock proteins by mass-spectrometric analysis of proteins obtained by GST-pulldown assay. Moreover, we created Crxp-ARMS2 and Crxp-HTRA1 transgenic mice to examine their role in the retina; their analysis is in progress.
Conclusions: :
Our data further confirms that ARMS2 is a mitochondrial protein and that TOMM40 is essential for its localization. A better understanding of ARMS2 function will be critical for delineating its involvement in AMD pathogenesis.
Keywords: age-related macular degeneration • mitochondria