title: Ankyrin B modulates the function of Na,K-ATPase/inositol 1,4,5-trisphosphate receptor signaling microdomain.
abstract: Na,K-ATPase and inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) can form a signaling microdomain that in the presence of ouabain triggers highly regular calcium oscillations. Downstream effects include NF-kappaB activation. Here we report that ankyrin B (Ank-B), expressed in most mammalian cells, plays a pivotal role in the function of the Na,K-ATPase/IP3R signaling microdomain. In studies performed on a monkey kidney cell line, we show that Ank-B co-precipitates with both Na,K-ATPase and IP3R. We identify the N terminus tail of the Na,K-ATPase catalytic subunit and the N-terminal portion 1-604 of the IP3R as novel binding sites for Ank-B. Knockdown of Ank-B with small interfering RNA reduced the expression of Ank-B to 15-30%. This down-regulation of Ank-B attenuated the interaction between Na,K-ATPase and IP3R, reduced the number of cells responding to pm doses of ouabain with calcium oscillations, altered the calcium oscillatory pattern, and abolished the ouabain effect on NF-kappaB. In contrast, Ank-B down-regulation had no effect on the ion transporting function of Na,K-ATPase and no effect on the distribution and apparent mobility of Na,K-ATPase in the plasma membrane.
authors.affiliation: Department of Woman and Child Health, Karolinska Institutet, Astrid Lindgren Children's Hospital, Q2:09, SE-171 76 Stockholm, Sweden.
authors.forename: Xiao
authors.initials: X
authors.lastname: Liu
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Spicarová
authors.forename: Susanna
authors.initials: S
authors.lastname: Rydholm
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Hjalmar
authors.initials: H
authors.lastname: Brismar
authors.forename: Anita
authors.initials: A
authors.lastname: Aperia
mesh_terms: D000818:Animals; D017487:Ankyrins / Q000378:metabolism / Q000502:physiology*; D019556:COS Cells; D002462:Cell Membrane / Q000201:enzymology; D002522:Chlorocebus aethiops; D015536:Down-Regulation; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D015398:Signal Transduction; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
chemical_list: C498994:ANK2 protein, human; D017487:Ankyrins; D053496:Inositol 1,4,5-Trisphosphate Receptors; D011994:Recombinant Proteins; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase