A new splice variant of glial fibrillary acidic protein, GFAPε, interacts with the presenilin proteins

We describe a new human isoform, GFAPepsilon, of the intermediary filament protein GFAP (glial fibrillary acidic protein). GFAPepsilon mRNA is the result of alternative splicing and a new polyadenylation signal, and thus GFAPepsilon has a new C-terminal protein sequence. This provides GFAPepsilon with the capacity for specific binding of presenilin proteins in yeast and in vitro. Our observations suggest a direct link between the presenilins and the cytoskeleton where GFAPepsilon is incorporated. Mutations in GFAP and presenilins are associated with Alexander disease and Alzheimer's disease, respectively. Accordingly, GFAPepsilon should be taken into consideration when studying neurodegenerative diseases.