title: The Ca2+ affinity of the plasma membrane Ca2+ pump is controlled by alternative splicing.
abstract: The plasma membrane Ca2+ pump is a calmodulin-regulated P-type ATPase that is an essential element in controlling intracellular Ca2+ concentration. Studies on the gene structure of this pump have revealed an alternate splice option that changes the structure of the calmodulin-binding domain. This change in the structure of the enzyme results in a reduced calmodulin affinity. Tests of the enzyme's activity in the presence of a high calmodulin concentration, approximating that found inside living cells, show that this reduced calmodulin affinity causes a reduced apparent affinity of the enzyme for Ca2+. This shift in the Ca2+ activation occurs in a Ca2+ concentration range crucial to cellular function and is probably the physiologically important consequence of the alternate splice.
authors.affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: A
authors.initials: A
authors.lastname: Enyedi
authors.forename: A K
authors.initials: AK
authors.lastname: Verma
authors.forename: R
authors.initials: R
authors.lastname: Heim
authors.forename: H P
authors.initials: HP
authors.lastname: Adamo
authors.forename: A G
authors.initials: AG
authors.lastname: Filoteo
authors.forename: E E
authors.initials: EE
authors.lastname: Strehler
authors.forename: J T
authors.initials: JT
authors.lastname: Penniston
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D006801:Humans; D008969:Molecular Sequence Data
chemical_list: D000252:Calcium-Transporting ATPases; D002118:Calcium