Isolation and characterization of a novel presenilin binding protein

Approximately 50% of familial Alzheimer's disease (AD) cases are linked to the presenilin (PS) gene. This suggests that an altered function of mutated PSs accounts for a fundamental process leading to AD. Here we identify a new PS binding protein, PBP, which is highly expressed in cerebral cortex and hippocampus. Immunohistochemical studies and cell fractionation analysis show that PBP redistributes from cytoplasm to membranes in the presence of PS. In addition, PBP is deficient in the soluble fraction of sporadic AD brains.