title: FAD-linked Presenilin-1 V97L mutation impede tranport regulation and intracellular Ca(2+) homeostasis under ER stress.
abstract: We report a PS1 gene mutation (Val 97Leu) in a Chinese familial Alzheimer's disease (FAD) pedigree and a cell model of FAD built by transfecting PS1 v97L mutants into human neuroblastoma SH-SY5Y cells. To test our hypothesis that the PS1 v97L mutation is pathogenic, we investigated possible alterations in transport regulation and intracellular Ca(2+) homeostasis in endoplasmic reticulum (ER). Grp78 is an ER-resident chaperone mediating the unfolded protein response (UPR) and is a key regulator of ER stress transducers. KDEL is a 4-amino-acid retention sequence made of Lys-Asp-Glu-Leu-COO. KDEL is a "resident" sequence as protein residence in ER is consistently associated with KDEL at the C-extremity. Our group used KDEL recognizing anti-Grp78 monoclonal antibody to detect the level of Grp78. We found increased KDEL level in all the transfected cells including cells transfected with PS1 V97L genes, wild-type and the mock. However cells with PS1 V97L mutation expressed a relatively lower KDEL compared with the wild-type and the mock, and a significantly lower Grp78 level compared with the wild-type, the mock and control. These results suggest that PS1 V97L mutation impedes intracellular transport regulation in ER. PS1 V97L mutation mediates increased ER Ca(2+) content in human neuroblastoma SH-SY5Y cells. The increased intracellular Ca(2+) release is due to depleted Ca(2+) storing content of ER but not due to extracellular environment as capacitative Ca(2+) entry (CCE) is invariant. PS1 V97L mutation interferes with intracellular Ca(2+) homeostasis. Abnormal transport regulation and Ca(2+) homeostasis attributed to PS1 V97L mutation may be associated with the pathology of Chinese familial FAD.
authors.affiliation: Department of Neurology, The China-Japan Union Hospital of Jilin University 130033, China.
authors.forename: Yankun
authors.initials: Y
authors.lastname: Shao
authors.affiliation: Department of Neurosurgery, The China-Japan Union Hospital of Jilin University 130033, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Neurology, The China-Japan Union Hospital of Jilin University 130033, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Wu
authors.affiliation: Department of Neurology, The China-Japan Union Hospital of Jilin University 130033, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Shi
authors.affiliation: Department of Neurology, Xuan Wu Hospital of The Capital University of Medical Sciences, Neurodegenerative Lab of Ministry of Education of The People's Republic of China Beijing 100053, China.
authors.forename: Boyan
authors.initials: B
authors.lastname: Fang
authors.affiliation: Department of Neurology, The China-Japan Union Hospital of Jilin University 130033, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
keywords: Ca2+ homeostasis; Familial alzheimer’s disease (FAD); gene mutation; ER stress; presenilin1 (PS1) genes