The Saccharomyces cerevisiae gene BTN1, encodes a 408 amino acid putative integral membrane protein, which is 39% identical and 59% similar to the human Cln3p, whose mutant forms are responsible for Batten's disease and for a diminished degradation of mitochondrial ATPase synthase subunit c. Disruption experiments established that Btn1p is not essential for viability, mitochondrial function, or degradation of mitochondrial ATP synthase in yeast.
Accumulating autofluorescent lysosomal storage material in CLN3 disease, consisting of dolichols, lipids, biometals, and a protein that normally resides in the mitochondria, subunit c of the mitochondrial ATPase, provides evidence that autophagosomal-lysosomal turnover of cellular components is disrupted upon loss of CLN3 protein function.