Thus, the observed slight increase in the number of spots in the Cartesian set depends only on the higher protein loading and not from differences in resolution. However, this increment was lower than what we would have expected on the basis of our experience with 2-DE. In fact, we have recently observed that, with a same protein load, a large gel allows to visualize nearly twice as many spots in respect to a gel of smaller dimension. This discrepancy could be related to the gel shape, which in this study balanced the difference in gel size. In conclusion, the gain in resolution obtained just by using a radial second-dimension gel can increase the resolution achieved during the IEF step. As a consequence, the comparative analysis reveals that, despite the smaller area, the absence of a gradient of porosity in the second dimension and the reduced loading, the radial set show a performance similar to the Cartesian one, but with the advantage of an associated increased reproducibility. Hence, for all the above-mentioned reasons, we retain that 2-PE appears an attractive innovation to further improve the performance of traditional two-dimensional gels. Subsequently, all the major cytosolic components have been established and the pathway is now D-Mannitol understood to be organized as a kinase signaling cascade that negatively regulates the downstream effector Yorkie. The function of the pathway is largely evolutionary conserved and mammalian homologs corresponding to all Drosophila Hippo proteins have been identified. These domains recognize proline-rich motifs facilitating protein�Cprotein interactions. In the nucleus, Yap1 functions as a transcriptional coactivator, initiating transcription in complex with various transcription factors, such as p73, EGR-1, Runx 1/2 and particularly the TEA domain family. The interactions with TEAD transcription factors are the only known interactions conserved from Drosophila to mammals. A main biological function of Yap1 is to promote cell proliferation through regulation of cell cycling and apoptosis. These functions are thus counteracted by the upstream Hippo components, resulting in a tight regulation of tissue homeostasis, as demonstrated in mouse models of altered Hippo signaling. Zhou and colleagues established that combined Mst1/Mst2 deficiency in the liver results in massive overgrowth and hepatocellular carcinoma as the loss of Mst1/Mst2 signaling abrogates Yap1 phosphorylation, leading to enhanced Yap1 activity in the nucleus and an increased transcriptional activity. Consistent with these consequences of perturbed Hippo signaling, several studies have demonstrated that overexpression of YAP1 in the liver results in a dramatic increase in cell proliferation and organ size. The profound role of Hippo signaling in regulating tissue homeostasis across different species raises the possibility of a functional importance in stem cells. In a transcriptional profiling study by Ramalho-Santos et al, comparing embryonic, neural and hematopoietic stem cells showed that Yap1 was one of a few genes with a consistently higher expression across the stem cell fractions compared to differentiated cells. More recently, these observations have been substantiated through functional studies of Yap1 in various stem cell types where Yap1 has been established as a vital factor in stem cell maintenance and proliferation. Cao and colleagues showed that YAP1 regulates neural progenitor cell number in the chick neural tube. It was further demonstrated that Yap1 is necessary for maintained pluripotency in Pseudoginsenoside-F11 murine embryonic stem cells and that ectopic expression of YAP1 prevents ES cell differentiation.