CLN -encoded proteins do not interact with each other

ABSTRACT

The lysosomal storage of lipofuscins is the common pathological feature that characterizes the infantile, late-infantile, juvenile (Batten's disease), and Finnish-variant neuronal ceroid lipofuscinosis (INCL, LINCL, JNCL and FNCL), which are due to mutations in the genes CLN1 , CLN2 , CLN3 , and CLN5 , respectively. The CLN1 and CLN2 genes encode lysosomal enzymes, but the CLN3 and CLN5 genes encode membrane-spanning proteins. Why deficiencies of lysosomal enzymes and membrane-spanning proteins produce similar clinical phenotypes and pathological changes is still unanswered. We hypothesize that CLN -encoded proteins may comprise a functional pathogenic pathway, in which protein associations may play important roles. To test this hypothesis, we studied protein-protein interactions among the CLN1 -, CLN2 -, and CLN3 -encoded proteins using a yeast two-hybrid system. Our results provided no evidence that CLN -encoded proteins interact with each other. This suggests there may be unidentified components in NCL pathogenesis.