title: Protein kinase A-regulated nucleocytoplasmic shuttling of Id1 during angiogenesis.
abstract: Id1, an inhibitory partner of basic-helix-loop-helix transcriptional factors, has recently been recognized as a potent contributor to angiogenesis. However, the molecular mechanism underlying its role in angiogenesis remains essentially unknown. Herein we demonstrate the subcellular localization of Id1 to be altered depending on the cellular context of vascular endothelial cells. Id1 was localized in the nuclei of human umbilical vein endothelial cells (HUVECs) cultured on uncoated plates, whereas it was translocated to the cytoplasm in HUVECs on Matrigel along with the formation of capillary-like structures. Treatment with the nuclear export inhibitor leptomycin B and mutagenesis analysis using green fluorescent protein-fused Id1 revealed CRM1/exportin-dependent nuclear export of Id1 in HUVECs on Matrigel. This nuclear export of Id1 was inhibited by protein kinase A (PKA) activation by dibutyryl cyclic AMP and forskolin but was promoted by PKA inactivation by H-89 and MDL-12,330A. Mutagenesis analysis of Id1 showed the phosphorylation of Ser-5 to possibly mediate the effect of PKA. These results suggest the function of Id1 as a transcriptional factor to be controlled by nucleocytoplasmic shuttling during angiogenesis and that PKA might be involved in this process. This may serve as a novel mechanism regulating angiogenesis and as a possible target for therapeutic vascular regeneration.
authors.affiliation: Department of Physiological Chemistry and Metabolism, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. nkanako@bio.m.u-tokyo.ac.jp
authors.forename: Koichi
authors.initials: K
authors.lastname: Nishiyama
authors.forename: Kentaro
authors.initials: K
authors.lastname: Takaji
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Uchijima
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kurihara
authors.forename: Tomoichiro
authors.initials: T
authors.lastname: Asano
authors.forename: Michihiro
authors.initials: M
authors.lastname: Yoshimura
authors.forename: Hisao
authors.initials: H
authors.lastname: Ogawa
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kurihara
mesh_terms: D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D017931:DNA Primers; D006801:Humans; D051798:Inhibitor of Differentiation Protein 1 / Q000378:metabolism*; D051379:Mice; D018919:Neovascularization, Physiologic; D010766:Phosphorylation; D021381:Protein Transport; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; C497455:Idb1 protein, mouse; D051798:Inhibitor of Differentiation Protein 1; D017868:Cyclic AMP-Dependent Protein Kinases