title: Microtubule-dependent redistribution of the type-1 inositol 1,4,5-trisphosphate receptor in A7r5 smooth muscle cells.
abstract: In A7r5 vascular smooth muscle cells, the two expressed inositol 1,4,5-trisphosphate receptor (IP(3)R) isoforms were differentially localized. IP(3)R1 was predominantly localized in the perinuclear region, whereas IP(3)R3 was homogeneously distributed over the cytoplasm. Prolonged stimulation (1-5 hours) of cells with 3 microM arginine-vasopressin induced a redistribution of IP(3)R1 from the perinuclear region to the entire cytoplasm, whereas the localization of IP(3)R3 appeared to be unaffected. The redistribution process occurred independently of IP(3)R downregulation. No structural changes of the endoplasmic reticulum were observed, but SERCA-type Ca(2+) pumps redistributed similarly to IP(3)R1. The change in IP(3)R1 localization induced by arginine-vasopressin could be blocked by the simultaneous addition of nocodazole or taxol and depended on Ca(2+) release from intracellular stores since Ca(2+)-mobilizing agents such as thapsigargin and cyclopiazonic acid could induce the redistribution. Furthermore, various protein kinase C inhibitors could inhibit the redistribution of IP(3)R1, whereas the protein kinase C activator 1-oleoyl-2-acetyl-sn-glycerol induced the redistribution. Activation of protein kinase C also induced an outgrowth of the microtubules from the perinuclear region into the cytoplasm, similar to what was seen for the redistribution of IP(3)R1. Finally, blocking vesicular transport at the level of the intermediate compartment inhibited the redistribution. Taken together, these findings suggest a role for protein kinase C and microtubuli in the redistribution of IP(3)R1, which probably occurs via a mechanism of vesicular trafficking.
authors.affiliation: Laboratory of Physiology, CME/VIB04, K.U. Leuven Campus Gasthuisberg O/N, Herestraat 49, B-3000 Leuven, Belgium.
authors.forename: Elke
authors.initials: E
authors.lastname: Vermassen
authors.forename: Kristel
authors.initials: K
authors.lastname: Van Acker
authors.forename: Wim G
authors.initials: WG
authors.lastname: Annaert
authors.forename: Bernard
authors.initials: B
authors.lastname: Himpens
authors.forename: Geert
authors.initials: G
authors.lastname: Callewaert
authors.forename: Ludwig
authors.initials: L
authors.lastname: Missiaen
authors.forename: Humbert
authors.initials: H
authors.lastname: De Smedt
authors.forename: Jan B
authors.initials: JB
authors.lastname: Parys
mesh_terms: D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D000252:Calcium-Transporting ATPases / Q000187:drug effects / Q000378:metabolism; D002451:Cell Compartmentation / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects / Q000378:metabolism*; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D022161:Transport Vesicles / Q000187:drug effects / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D004791:Enzyme Inhibitors; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D001127:Arginine Vasopressin; D011493:Protein Kinase C; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases