The β-Amyloid protein precursor (AbPP) is a widely expressed transmembrane protein that is processed into the b-Amyloid (Ab) peptide, which accumulates in insoluble plaques in the brain of Alzheimer’s disease patients and AbPP intracellular domain (AID). AID may function as a pro-apoptotic peptide, a regulator of calcium homeostasis and a molecule involved in transcriptional regulation. The AID associated protein 1 (AIDA-1) is highly expressed in the brain and is regulated by AbPP. It interacts with AbPP to play a role in brain development. AIDA-1 also interacts with coilin in Cajal bodies to regulate pre-mRNA splicing.