of the Project Pediatric cataract is the most common form of childhood blindness and is both clinically and genetically heterogeneous. Autosomal dominant and recessive forms of cataract have been reported to be caused by mutations in nearly 22 different genes so far. More than half of the muitants occur in crystallins, in ?A- and ?B-crystallins mostly. This proposal is aimed to investigate the possibility that mutations in ?A- and ?B-crystallins cause cataract by introducing significant conformational changes which will initiate a cascade of events leading to dysfunctional molecular chaperones lacking the ability to interact with native ?A- and ?B-crystallins and the various protein substrates. For this study, we have selected 8 mutants of ?A-crystallin and 4 mutants of ?B-crystallin, all known to be responsible for congenital cataracts. We will study 1) the structural, functional and hydrodynamic properties of these mutants in the homooligomeric and heterooligomeric forms (Aims 1 &2), 2) the interaction of the mutants with ?A-wt and ?B-wt by using FRET in an in vitro system (Aim 3), and 3) study the expression of the mutants and their interaction with ?A-wt and ?B-wt using FRET and asses the presence of protein aggregates, while each mutant is expressed alone or co-expressed with ?A-wt or ?B-wt in mammalian cells. These studies are expected to show the underlying mechanism by which various mutants cause cataract in the affected individuals.
Summary for public interest Pediatric cataract is the most common form of childhood blindness. Globally, about 20 million children under the age of 16 suffer from cataract and among them about 15% are severely visually impaired or blind. The present study is about analyzing the mutated proteins in the eye lens with a goal to unravel the underlying mechanism of cataract development.
|Kore, Rajshekhar A; Abraham, Edathara C (2016) Phosphorylation negatively regulates exosome mediated secretion of cryAB in glioma cells. Biochim Biophys Acta 1863:368-77|
|Kore, Rajshekhar A; Abraham, Edathara C (2014) Inflammatory cytokines, interleukin-1 beta and tumor necrosis factor-alpha, upregulated in glioblastoma multiforme, raise the levels of CRYAB in exosomes secreted by U373 glioma cells. Biochem Biophys Res Commun 453:326-31|
|Raju, Ilangovan; Abraham, Edathara C (2013) Mutants of human Î±B-crystallin cause enhanced protein aggregation and apoptosis in mammalian cells: influence of co-expression of HspB1. Biochem Biophys Res Commun 430:107-12|
|Raju, Ilangovan; Oonthonpan, Lalita; Abraham, Edathara C (2012) Mutations in human Ã½Ã½A-crystallin/sHSP affect subunit exchange interaction with Ã½Ã½B-crystallin. PLoS One 7:e31421|
|Kore, Rajshekhar; Hedges, Rebecca A; Oonthonpan, Lalita et al. (2012) Quaternary structural parameters of the congenital cataract causing mutants of Ã½Ã½A-crystallin. Mol Cell Biochem 362:93-102|
|Raju, Ilangovan; Kumarasamy, Anbarasu; Abraham, Edathara C (2011) Multiple aggregates and aggresomes of C-terminal truncated human Ã½Ã½A-crystallins in mammalian cells and protection by Ã½Ã½B-crystallin. PLoS One 6:e19876|
|Raju, Ilangovan; Abraham, Edathara C (2011) Congenital cataract causing mutants of Ã½Ã½A-crystallin/sHSP form aggregates and aggresomes degraded through ubiquitin-proteasome pathway. PLoS One 6:e28085|
|Kumarasamy, Anbarasu; Abraham, Edathara C (2008) Interaction of C-terminal truncated human alphaA-crystallins with target proteins. PLoS One 3:e3175|
|Datta, Poppy; Kallur, Latha; Abraham, Edathara C (2008) Reversal of chaperone activity loss of glycated alphaA-crystallin by a crosslink breaker. Mol Cell Biochem 315:137-42|
|Abraham, Edathara C; Huaqian, Jin; Aziz, Atya et al. (2008) Role of the specifically targeted lysine residues in the glycation dependent loss of chaperone activity of alpha A- and alpha B-crystallins. Mol Cell Biochem 310:235-9|
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