DETERMINATION OF A CLEAVAGE SITE OF PRESENILIN-2 PROTEIN IN STABLY TRANSFECTED SH-SY5Y HUMAN NEUROBLASTOMA CELL-LINES

Mutations in the presenilin 1 (PS1) and presenilin 2 (PS2) genes are a ssociated with early-onset autosomal dominant familial Alzheimer's dis ease, and the gene products are endoproteolytically processed to yield N-terminal fragments (NTF) and C-terminal fragments (CTF). We have st udied the cleavage site of the PS2 protein in stably transfected human neuroblastoma cells. The 23 kD PS2-CTF was isolated by a combination of anion exchange chromatography and affinity chromatography and direc tly sequenced. The N-terminus of the PS2-CTF started at residue 307, w hich indicated that the cleavage occurs between Lys(306) and Leu(307) in the proximal portion of the large hydrophilic loop. This site is cl ose to the cleavage positions observed in the PS1 protein. (C) 1997 Ac ademic Press.