title: Coincident microvillar actin bundle disruption and perinuclear actin sequestration in anoxic proximal tubule.
abstract: The present studies investigated acute disruption of microvillar actin cytoskeleton and actin association with other cytoskeletal components in ATP-depleted rabbit proximal tubular cells. Video-enhanced differential-interference contrast microscopy and confocal microscopy were used to follow the fate of F-actin during the disruption of microvilli. Within individual cells, all microvilli collapsed simultaneously. Microvillar actin filaments underwent a parallel decrease in length. Using a sequential cytoskeletal extraction protocol and electron microscopy, we revealed in the present studies the coincident sequestration of a distinct, perinuclear pool of actin that was primarily absent in control cells. Actin sequestration progressed in a duration-dependent manner, occurring as early as 15 min of anoxia when cellular ATP dropped to <5% of control level. Phalloidin staining and depolymerization treatment showed the majority (>90%) of this sequestered actin to be F-actin. A microvillar actin bundling protein villin was also sequestered in the same perinuclear complex of anoxic proximal tubules. In conclusion, the present results demonstrate a coincident microvillar actin bundle disruption and the perinuclear sequestration of F-actin in ATP-depleted proximal tubular cells.
authors.affiliation: Department of Life Sciences, Indiana State University, Terre Haute 47809, USA.
authors.forename: P
authors.initials: P
authors.lastname: White
authors.forename: R B
authors.initials: RB
authors.lastname: Doctor
authors.forename: R H
authors.initials: RH
authors.lastname: Dahl
authors.forename: J
authors.initials: J
authors.lastname: Chen
mesh_terms: D000199:Actins / Q000378:metabolism* / Q000648:ultrastructure*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002451:Cell Compartmentation; D015687:Cell Hypoxia / Q000502:physiology; D003599:Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D066298:In Vitro Techniques; D007687:Kidney Tubules, Proximal / Q000378:metabolism* / Q000648:ultrastructure*; D018715:Microscopy, Video; D008871:Microvilli / Q000378:metabolism / Q000648:ultrastructure; D011817:Rabbits; D012995:Solubility
chemical_list: D000199:Actins; D000255:Adenosine Triphosphate