title: AKAP12 regulates vascular integrity in zebrafish.
abstract: The integrity of blood vessels controls vascular permeability and extravasation of blood cells, across the endothelium. Thus, the impairment of endothelial integrity leads to hemorrhage, edema, and inflammatory infiltration. However, the molecular mechanism underlying vascular integrity has not been fully understood. Here, we demonstrate an essential role for A-kinase anchoring protein 12 (AKAP12) in the maintenance of endothelial integrity during vascular development. Zebrafish embryos depleted of akap12 (akap12 morphants) exhibited severe hemorrhages. In vivo time-lapse analyses suggested that disorganized interendothelial cell-cell adhesions in akap12 morphants might be the cause of hemorrhage. To clarify the molecular mechanism by which the cell-cell adhesions are impaired, we examined the cell-cell adhesion molecules and their regulators using cultured endothelial cells. The expression of PAK2, an actin cytoskeletal regulator, and AF6, a connector of intercellular adhesion molecules and actin cytoskeleton, was reduced in AKAP12-depleted cells. Depletion of either PAK2 or AF6 phenocopied AKAP12-depleted cells, suggesting the reduction of PAK2 and AF6 results in the loosening of intercellular junctions. Consistent with this, overexpression of PAK2 and AF6 rescued the abnormal hemorrhage in akap12 morphants. We conclude that AKAP12 is essential for integrity of endothelium by maintaining the expression of PAK2 and AF6 during vascular development.
authors.affiliation: NeuroVascular Coordination Research Center, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea.
authors.forename: Hyouk-Bum
authors.initials: HB
authors.lastname: Kwon
authors.forename: Yoon Kyung
authors.initials: YK
authors.lastname: Choi
authors.forename: Jhong-Jae
authors.initials: JJ
authors.lastname: Lim
authors.forename: Seung-Hae
authors.initials: SH
authors.lastname: Kwon
authors.forename: Song
authors.initials: S
authors.lastname: Her
authors.forename: Hyun-Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Kyung-Joon
authors.initials: KJ
authors.lastname: Lim
authors.forename: Jong-Chan
authors.initials: JC
authors.lastname: Ahn
authors.forename: Young-Myeong
authors.initials: YM
authors.lastname: Kim
authors.forename: Moon-Kyung
authors.initials: MK
authors.lastname: Bae
authors.forename: Jeong Ae
authors.initials: JA
authors.lastname: Park
authors.forename: Chul-Ho
authors.initials: CH
authors.lastname: Jeong
authors.forename: Naoki
authors.initials: N
authors.lastname: Mochizuki
authors.forename: Kyu-Won
authors.initials: KW
authors.lastname: Kim
mesh_terms: D054758:A Kinase Anchor Proteins / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001808:Blood Vessels / Q000002:abnormalities / Q000196:embryology* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D004625:Embryo, Nonmammalian / Q000002:abnormalities / Q000098:blood supply* / Q000196:embryology / Q000378:metabolism; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D006470:Hemorrhage / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D007365:Intercellular Junctions / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D016547:Kinesins / Q000235:genetics / Q000378:metabolism; D009218:Myosins / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D054462:p21-Activated Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D054758:A Kinase Anchor Proteins; C095516:AFDN protein, human; C491162:AKAP12 protein, human; D018797:Cell Cycle Proteins; D054462:p21-Activated Kinases; D009218:Myosins; D016547:Kinesins