title: VERO cells harbor a poly-ADP-ribose belt partnering their epithelial adhesion belt.
abstract: Poly-ADP-ribose (PAR) is a polymer of up to 400 ADP-ribose units synthesized by poly-ADP-ribose-polymerases (PARPs) and degraded by poly-ADP-ribose-glycohydrolase (PARG). Nuclear PAR modulates chromatin compaction, affecting nuclear functions (gene expression, DNA repair). Diverse defined PARP cytoplasmic allocation patterns contrast with the yet still imprecise PAR distribution and still unclear functions. Based on previous evidence from other models, we hypothesized that PAR could be present in epithelial cells where cadherin-based adherens junctions are linked with the actin cytoskeleton (constituting the adhesion belt). In the present work, we have examined through immunofluorescence and confocal microscopy, the subcellular localization of PAR in an epithelial monkey kidney cell line (VERO). PAR was distinguished colocalizing with actin and vinculin in the epithelial belt, a location that has not been previously reported. Actin filaments disruption with cytochalasin D was paralleled by PAR belt disruption. Conversely, PARP inhibitors 3-aminobenzamide, PJ34 or XAV 939, affected PAR belt synthesis, actin distribution, cell shape and adhesion. Extracellular calcium chelation displayed similar effects. Our results demonstrate the existence of PAR in a novel subcellular localization. An initial interpretation of all the available evidence points towards TNKS-1 as the most probable PAR belt architect, although TNKS-2 involvement cannot be discarded. Forthcoming research will test this hypothesis as well as explore the existence of the PAR belt in other epithelial cells and deepen into its functional implications.
authors.affiliation: Departamento de Genética, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE) , Montevideo , Uruguay.
authors.forename: Laura
authors.initials: L
authors.lastname: Lafon-Hughes
authors.affiliation: Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres", Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires , Argentina.
authors.forename: Salomé C
authors.initials: SC
authors.lastname: Vilchez Larrea
authors.affiliation: Departamento de Proteínas y Ácidos Nucleicos, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE) , Montevideo , Uruguay ; Departamento de Biología Celular y Molecular, Sección Bioquímica, Facultad de Ciencias, Universidad de la República , Montevideo , Uruguay.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Kun
authors.affiliation: Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres", Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires , Argentina ; Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires , Argentina.
authors.forename: Silvia H
authors.initials: SH
authors.lastname: Fernández Villamil
keywords: Actin; Adherens junctions; Alpha-catenin; E-cadherin; PAR; PARP; PJ34; Tankyrase; Vinculin; XAV 939