title: SERCA pump activity is physiologically regulated by presenilin and regulates amyloid beta production.
abstract: In addition to disrupting the regulated intramembraneous proteolysis of key substrates, mutations in the presenilins also alter calcium homeostasis, but the mechanism linking presenilins and calcium regulation is unresolved. At rest, cytosolic Ca(2+) is maintained at low levels by pumping Ca(2+) into stores in the endoplasmic reticulum (ER) via the sarco ER Ca(2+)-ATPase (SERCA) pumps. We show that SERCA activity is diminished in fibroblasts lacking both PS1 and PS2 genes, despite elevated SERCA2b steady-state levels, and we show that presenilins and SERCA physically interact. Enhancing presenilin levels in Xenopus laevis oocytes accelerates clearance of cytosolic Ca(2+), whereas higher levels of SERCA2b phenocopy PS1 overexpression, accelerating Ca(2+) clearance and exaggerating inositol 1,4,5-trisphosphate-mediated Ca(2+) liberation. The critical role that SERCA2b plays in the pathogenesis of Alzheimer's disease is underscored by our findings that modulating SERCA activity alters amyloid beta production. Our results point to a physiological role for the presenilins in Ca(2+) signaling via regulation of the SERCA pump.
authors.affiliation: Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA.
authors.forename: Kim N
authors.initials: KN
authors.lastname: Green
authors.forename: Angelo
authors.initials: A
authors.lastname: Demuro
authors.forename: Yama
authors.initials: Y
authors.lastname: Akbari
authors.forename: Brian D
authors.initials: BD
authors.lastname: Hitt
authors.forename: Ian F
authors.initials: IF
authors.lastname: Smith
authors.forename: Ian
authors.initials: I
authors.lastname: Parker
authors.forename: Frank M
authors.initials: FM
authors.lastname: LaFerla
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics; D019943:Amino Acid Substitution; D016229:Amyloid beta-Peptides / Q000096:biosynthesis*; D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation / Q000235:genetics; D053764:Presenilin-1 / Q000172:deficiency / Q000378:metabolism*; D053766:Presenilin-2 / Q000172:deficiency / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D004791:Enzyme Inhibitors; D053764:Presenilin-1; D053766:Presenilin-2; D015544:Inositol 1,4,5-Trisphosphate; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D002118:Calcium