Association of type 1 inositol 1,4,5-trisphosphate receptor with AKAP9 (Yotiao) and protein kinase A.
Inositol 1,4,5-trisphosphate receptors (InsP(3)R) play a key role in intracellular calcium (Ca(2+)) signaling. Three InsP(3)R isoforms are expressed in mammals. Type 1 InsP(3)R (InsP(3)R1) is a predominant neuronal isoform. Neuronal InsP(3)R1 is one of the major substrates of protein kinase A (PKA) phosphorylation. In our previous study (Tang, T. S., Tu, H., Wang, Z., and Bezprozvanny, I. (2003) J. Neurosci. 23, 403-415) we discovered a direct association between InsP(3)R1 and protein phosphatase 1 alpha (PP1 alpha). In functional experiments we demonstrated that phosphorylation by PKA activates InsP(3)R1 and that dephosphorylation by PP1 alpha inhibits InsP(3)R1. To extend these findings, here we investigated the possibility of InsP(3)R1-PKA association. In a series of biochemical experiments we demonstrate the following findings. 1) InsP(3)R1 and PKA associate in the brain. 2) InsP(3)R1-PKA association is mediated by the AKAP9 (Yotiao) multi-functional PKA anchoring protein. 3) InsP(3)R1-AKAP9 association is mediated via the leucine/isoleucine zipper (LIZ) motif in the InsP(3)R1 coupling domain and the fourth LIZ motif in AKAP9. 4) The InsP(3)R association with AKAP9 is specific for type 1 InsP(3)R. 5) Both the SII(+) and the SII(-) coupling domain splice variants of InsP(3)R1 bind to AKAP9. 6) Binding to AKAP9 promotes association of neuronal InsP(3)R1 with the NR1 NMDA receptor; and 7) neuronal InsP(3)R1 associate with PP1 directly via carboxy-terminus and indirectly via AKAP9. The obtained results advance our understanding of cross-talk between cAMP and InsP(3)/Ca(2+) signaling pathways in the brain.
Tu
Huiping
H
Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9040, USA.
Tang
Tie-Shan
TS
Wang
Zhengnan
Z
Bezprozvanny
Ilya
I
D054758:A Kinase Anchor Proteins; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001665:Binding Sites; D001921:Brain; D001923:Brain Chemistry; D015220:Calcium Channels / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate; D053496:Inositol 1,4,5-Trisphosphate Receptors; D016350:Leucine Zippers; D011485:Protein Binding; D051381:Rats; D020239:Receptor Cross-Talk; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D015398:Signal Transduction
D054758:A Kinase Anchor Proteins; C119719:AKAP9 protein, human; D048868:Adaptor Proteins, Signal Transducing; C486537:Akap9 protein, rat; D015220:Calcium Channels; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D015544:Inositol 1,4,5-Trisphosphate; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases