Colocalization Analysis of PPP1 Isoforms and Two Novel Targeting Subunits in Breast Carcinoma

Abstract

Protein phosphatase 1 (PPP1) is the PPP most ubiquitous and each isoform interact with regulatory subunits that may be responsible for their subcellular localization. We identified PPP1R15B, C1ORF71 as novel regulators and the aim of this study was their further characterization in carcinoma cells. We analysed localization of each regulator in MDA-MB-468 cells and we transfected with constructs that we made with each as a GFP-fusion protein. For PPP1 cellular localization we used specific antibodies for each isoform. We observed the cells under a fluorescent microscope and LSM and we quantified co-localization. We found a high overlap coefficient of both the novel proteins with PPP1alpha and PPP1gamma1.We propose a model in which PPP1 regulator interacts with one or two regulatory subunits that may be used as target for therapeutic strategies.KEY-WORDS Fluorescent microscopy, laser scanning microscopy, overlap coefficient, PPP1, novel regulators, breast carcinoma ACKNOWLEDGMENTS This work was supported by FCT: CS received a PhD fellowship, and A.P.V. and M.F. received pos-doctoral fellowships.