C9orf72 Antibody #64196

The expansion of hexanucleotide GGGGCC repeats in the C9orf72 gene causes chromosome 9p-linked neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (1,2). The specific mechanism by which of these repeats contributes to disease etiology is currently an active area of investigation (3). Several gain of function mechanisms have been proposed. These mechanisms include toxicity from C9orf72 RNA containing the hexanucleotide repeats (4) and toxicity generated from dipeptide repeat proteins produced by repeat-associated non-ATG translation (5). In addition to gain of function mechanisms, the genetic hexanucleotide repeat expansions may cause a loss of function of the C9orf72 protein. C9orf72 contains a predicted DENN (differentially expressed in normal and neoplastic cells) domain that typically functions as guanine exchange factors for Rab GTPases, proteins that play key regulatory roles in membrane trafficking (6). Consistent with C9orf72 normally functioning in membrane trafficking, biochemical and genetic studies revealed that C9orf72 forms a protein complex with Sim-Magenis chromosome region 8 (SMCR8) and WD repeat-containing protein 41 (WDR41) to regulate the autophagy-lysosomal pathway (7), suggesting that C9orf72-dependent alterations in the autophagy-lysosomal pathway might contribute to ALS/FTD pathology.