VERO CELLS HARBOR A POLY(ADP-RIBOSE) BELT PARTNERING THEIR ADHESION BELT

LAURA LAFON-HUGHES; SALOMÉ C. VILCHEZ LARREA; ALEJANDRA KUN; SILVIA FERNANDEZ VILLAMIL

Rosario

Congreso; L Congreso de la Sociedad Argentina de Investigaciones Bioquimicas y Biologia Molecular; 2014

SAIB

Poly-ADP-ribose-polymerase (PARP) family members synthesize poly-ADP-ribose (PAR) both in cell nuclei and cytoplasm. While it is clear that nuclear PAR modulates chromatin compaction, affecting nuclear functions (gene expression, DNA repair), PAR cytoplasmic distributions and functions are still ill-defined. We have examined through immunofluorescence and confocal microscopy, the subcellular localization of PAR in an epithelial cell line (VERO). Actin filaments disruption with cytochalasin D was paralleled by PAR belt disruption. Conversely, PARP inhibitors 3-aminobenzamide, PJ34 or XAV 939, but not Olaparib, 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. We propose for the first time that cytoplasmic PAR would be involved in adherens junction complexes that connect E-cadherin, α- and β-catenin, vinculin and actin microfilaments in polarized epithelial cells. The present work expands our perspectives regarding PAR functions, with deep implications in pathological situations, where PAR abundance or scarcity may affect the epithelial structure as well as transcendent cell signaling pathways.