2.A.57.5.8
Battenin or Cln3, of 438 aas and 11 TMSs, is phosphorylated on both serine and threonine residues by three protein kinases (Michalewski et al. 1998). The N-terminus of Battenin is a protein interaction domain (Moroziewicz et al. 2006). Cln3 is involved in microtubule-dependent, anterograde transport of late endosomes and lysosomes. CLN3 interacts directly with active, guanosine-5'-triphosphate (GTP)-bound Rab7 and with the Rab7-interacting lysosomal protein (RILP) that anchors the dynein motor (Uusi-Rauva et al. 2012). Loss-of-function mutations in CLN3 are responsible for juvenile-onset neuronal ceroid lipofuscinosis (JNCL), or Batten disease, which is an incurable lysosomal disease that manifests with vision loss, followed by seizures and progressive neurodegeneration, robbing children of motor skills, speech and cognition, and eventually leading to death in the second or third decade of life. A current understanding of CLN3 structure, function and dysfunction in JNCL can be found in (Cotman and Staropoli 2012). Mutational variability in CLN3 gives rise to JNCL (Sher et al. 2019). The N-terminus of Battenin is a protein interaction domain (Moroziewicz et al. 2006). Dysregulation of intracellular calcium homeostasis results from the absence of a functional CLN3 protein. and has been linked to synaptic dysfunction and accelerated apoptosis in vulnerable neuronal cells. Prolonged increased intracellular calcium may be a trigger for neuronal apoptosis and cellular loss in JNCL (An Haack et al. 2011).