title: Plasma membrane Ca²⁺-ATPases can shape the pattern of Ca²⁺ transients induced by store-operated Ca²⁺ entry.
abstract: Calcium (Ca(2+)) is a critical cofactor and signaling mediator in cells, and the concentration of cytosolic Ca(2+) is regulated by multiple proteins, including the plasma membrane Ca(2+)-ATPases (adenosine triphosphatases) (PMCAs), which use ATP to transport Ca(2+) out of cells. PMCA isoforms exhibit different kinetic and regulatory properties; thus, the presence and relative abundance of individual isoforms may help shape Ca(2+) transients and cellular responses. We studied the effects of three PMCA isoforms (PMCA4a, PMCA4b, and PMCA2b) on Ca(2+) transients elicited by conditions that trigger store-operated Ca(2+) entry (SOCE) and that blocked Ca(2+) uptake into the endoplasmic reticulum in HeLa cells, human embryonic kidney (HEK) 293 cells, or primary endothelial cell isolated from human umbilical cord veins (HUVECs). The slowly activating PMCA4b isoform produced long-lasting Ca(2+) oscillations in response to SOCE. The fast-activating isoforms PMCA2b and PMCA4a produced different effects. PMCA2b resulted in rapid and highly PMCA abundance-sensitive clearance of SOCE-mediated Ca(2+) transients, whereas PMCA4a reduced cytosolic Ca(2+), resulting in the establishment of a higher than baseline cytosolic Ca(2+) concentration. Mathematical modeling showed that slow activation was critical to the sustained oscillation induced by the "slow" PMCA4b pump. The modeling and experimental results indicated that the distinct properties of PMCA isoforms differentially regulate the pattern of SOCE-mediated Ca(2+) transients, which would thus affect the activation of downstream signaling pathways.
authors.affiliation: Molecular Biophysics Research Group of the Hungarian Academy of Sciences and Department of Biophysics, Semmelweis University, Budapest H-1094, Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Pászty
authors.affiliation: Hematology Research, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Ariel J
authors.initials: AJ
authors.lastname: Caride
authors.affiliation: Division of Biomathematics, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905, USA. Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Željko
authors.initials: Ž
authors.lastname: Bajzer
authors.affiliation: Molecular Medicine Program, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Chetan P
authors.initials: CP
authors.lastname: Offord
authors.affiliation: Hungarian National Blood Transfusion Service, Budapest H-1113, Hungary. 2nd Department of Pathology, Semmelweis University, Budapest H-1091, Hungary.
authors.forename: Rita
authors.initials: R
authors.lastname: Padányi
authors.affiliation: Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest H-1117, Hungary.
authors.forename: Luca
authors.initials: L
authors.lastname: Hegedűs
authors.affiliation: 2nd Department of Pathology, Semmelweis University, Budapest H-1091, Hungary. Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest H-1117, Hungary.
authors.forename: Karolina
authors.initials: K
authors.lastname: Varga
authors.affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Emanuel E
authors.initials: EE
authors.lastname: Strehler
authors.affiliation: Hungarian National Blood Transfusion Service, Budapest H-1113, Hungary. 2nd Department of Pathology, Semmelweis University, Budapest H-1091, Hungary. Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest H-1117, Hungary. enyedi.agnes@med.semmelweis-univ.hu.
authors.forename: Agnes
authors.initials: A
authors.lastname: Enyedi
mesh_terms: D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology*; D003600:Cytosol / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D008954:Models, Biological; D020033:Protein Isoforms / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D020033:Protein Isoforms; D000252:Calcium-Transporting ATPases; D002118:Calcium