title: ERK binds, phosphorylates InsP3 type 1 receptor and regulates intracellular calcium dynamics in DT40 cells.
abstract: Modulation on the duration of intracellular Ca(2+) transients is essential for B-cell activation. We have previously shown that extracellular-signal-regulated kinase (ERK) can phosphorylate inositol 1,4,5-trisphosphate receptor type 1 (IP(3)R1) at serine 436 and regulate its calcium channel activity. Here we investigate the potential physiological interaction between ERK and IP(3)R1 using chicken DT40 B-cell line in which different mutants are expressed. The interaction between ERK and IP(3)R1 is confirmed by co-immunoprecipitation and fluorescence resonance energy transfer (FRET) assays. This constitutive interaction is independent of either ERK kinase activation or IP(3)R1 phosphorylation status. Back phosphorylation analysis further shows that type 1 IP(3)R (IP(3)R1) is phosphorylated by ERK in anti-IgM-activated DT40 cells. Finally, our data show that the phosphorylation of Ser 436 in the IP(3)-binding domain of IP(3)R1 leads to less Ca(2+) release from endoplasmic reticulum (ER) microsomes and accelerates the declining of calcium increase in DT40 cells in response to anti-IgM stimulation.
authors.affiliation: Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, China.
authors.forename: Ling-Hai
authors.initials: LH
authors.lastname: Yang
authors.forename: Gui-Rong
authors.initials: GR
authors.lastname: Bai
authors.forename: Xiu-Ying
authors.initials: XY
authors.lastname: Huang
authors.forename: Fang-Zhen
authors.initials: FZ
authors.lastname: Sun
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D002460:Cell Line; D002645:Chickens; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005246:Feedback / Q000502:physiology; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism*; D007700:Kinetics; D010766:Phosphorylation; D011485:Protein Binding
chemical_list: D053496:Inositol 1,4,5-Trisphosphate Receptors; D048049:Extracellular Signal-Regulated MAP Kinases; D002118:Calcium