title: Ultrastructural Localization of Endogenous Exchange Factor for ARF6 in Adrenocortical Cells In Situ of Mice.
abstract: EFA6 (exchange factor for ARF6) activates Arf6 (ADP ribosylation factor 6) by exchanging ADP to ATP, and the resulting activated form of Arf6 is involved in the membrane dynamics and actin re-organization of cells. The present study was attempted to localize EFA6 type D (EFA6D) in mouse adrenocortical cells in situ whose steroid hormone secretion is generally considered not to depend on the vesicle-involved regulatory mechanism. In immunoblotting, an immunoreactive band with the same size as brain EFA6D was detected in homogenates of adrenal cortical tissues almost free of adrenal capsules and medulla. In immuno-light microscopy, EFA6D-immunoreactivity was positive in adrenocortical cells and it was often distinct along the plasmalemma, especially along portions of the cell columns facing the interstitium. In immuno-electron microscopy, the gold-labeling was more dense in the peripheral intracellular domains than the central domain of the immunopositive cells. The labeling was deposited on the plasma membranes in a discontinuous pattern and in cytoplasmic domains rich in filaments. It was also associated with some, but not all, of pleiomorphic vesicles and coated pits/vesicles. No labeling was seen in association with lipid droplets or smooth endoplasmic reticulum. The present finding is in support of the importance of EFA6D for activation of Arf6 in adrenocortical cells.
authors.affiliation: Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Muang, Khon Kaen, Thailand; Neuroscience Research and Development Group, Khon Kaen University, Muang, Khon Kaen, Thailand.
authors.forename: Surang
authors.initials: S
authors.lastname: Chomphoo
authors.affiliation: Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University , Muang, Khon Kaen, Thailand.
authors.forename: Wilaiwan
authors.initials: W
authors.lastname: Mothong
authors.affiliation: Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University , Muang, Khon Kaen, Thailand.
authors.forename: Tarinee
authors.initials: T
authors.lastname: Sawatpanich
authors.affiliation: Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University , Muang, Khon Kaen, Thailand.
authors.forename: Pipatphong
authors.initials: P
authors.lastname: Kanla
authors.affiliation: Department of Anatomy, School of Medicine, Kitasato University , Tokyo.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sakagami
authors.affiliation: Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University , Muang, Khon Kaen, Thailand.
authors.forename: Hisatake
authors.initials: H
authors.lastname: Kondo
authors.affiliation: Electron Microscopy Laboratory, Department of Anatomy, Faculty of Medicine, Khon Kaen University , Muang, Khon Kaen, Thailand.
authors.forename: Wiphawi
authors.initials: W
authors.lastname: Hipkaeo
keywords: EFA6D; adrenal cortex; membrane dynamics; mice; ultrastructure