PKD1 Phosphorylation-Dependent Degradation of SNAIL by SCF-FBXO11 Regulates Epithelial-Mesenchymal Transition and Metastasis

SummaryMetastatic dissemination is often initiated by the reactivation of an embryonic development program referred to as epithelial-mesenchymal transition (EMT). The transcription factor SNAIL promotes EMT and elicits associated pathological characteristics such as invasion, metastasis, and stemness. To better understand the posttranslational regulation of SNAIL, we performed a luciferase-based, genome-wide E3 ligase siRNA library screen and identified SCF-FBXO11 as an important E3 that targets SNAIL for ubiquitylation and degradation. Furthermore, we discovered that SNAIL degradation by FBXO11 is dependent on Ser-11 phosphorylation of SNAIL by protein kinase D1 (PKD1). FBXO11 blocks SNAIL-induced EMT, tumor initiation, and metastasis in multiple breast cancer models. These findings establish the PKD1-FBXO11-SNAIL axis as a mechanism of posttranslational regulation of EMT and cancer metastasis

fast soft shadow by depth peeling

ACM Spec. Interest Group Comput.; Graph. Interact. Tech. (SIGGRAPH)Soft shadow generation is a challenging problem in realistic rendering. Previous methods using shadow map or shadow volume work well for point light sources but are difficult to be extended to area lights. This paper presents a new method for fast soft shadow generation under dynamic area light sources. Our algorithm encodes the depth distribution of the scene into a coarse depth grid in a preliminary pass from the light point of view. In the second pass, the scene is rendered from the camera viewpoint to capture the frontmost layer. During deferred shading, the area light is sampled and the irradiance of each shaded pixel is accumulated along the ray. Experimental results demonstrate high quality soft shadows with interactive performance for dynamic scenes and lighting. © ACM 2010

Ultralow Laser Power Three-Dimensional Superresolution Microscopy Based on Digitally Enhanced STED

The resolution of optical microscopes is limited by the optical diffraction limit; in particular, the axial resolution is much lower than the lateral resolution, which hinders the clear distinction of the three-dimensional (3D) structure of cells. Although stimulated emission depletion (STED) superresolution microscopy can break through the optical diffraction limit to achieve 3D superresolution imaging, traditional 3D STED requires high depletion laser power to acquire high-resolution images, which can cause irreversible light damage to biological samples and probes. Therefore, we developed an ultralow laser power 3D STED superresolution imaging method. On the basis of this method, we obtained lateral and axial resolutions of 71 nm and 144 nm, respectively, in fixed cells with 0.65 mW depletion laser power. This method will have broad application prospects in 3D superresolution imaging of living cells

Deubiquitinase USP20 promotes breast cancer metastasis by stabilizing SNAI2

SNAI2/SLUG, a metastasis-promoting transcription factor, is a labile protein that is degraded through the ubiquitin proteasome degradation system. Here, we conducted comprehensive gain- and loss-of-function screens using a human DUB cDNA library of 65 genes and an siRNA library of 98 genes, and identified USP20 as a deubiquitinase (DUB) that regulates SNAI2 ubiquitination and stability. Further investigation of USP20 demonstrated its function in promoting migration, invasion, and metastasis of breast cancer. USP20 positively correlates with SNAI2 protein level in breast tumor samples, and higher USP20 expression is associated with poor prognosis in ER- breast cancer patients