Abstract 1130: Subcellular localization of the cell polarity protein Scribble defines its oncogenic activity in hepatocellular carcinoma

Author(s):  
Shan Wan ◽  
Anne-Sophie Meyer ◽  
Sofia Weiler ◽  
Teresa Lutz ◽  
Stephanie Roessler ◽  
...  
2020 ◽  
Vol 245 (5) ◽  
pp. 385-394 ◽  
Author(s):  
Lucía Barbier-Torres ◽  
Shelly C Lu

Prohibitin 1 is an evolutionary conserved and ubiquitously expressed protein that exerts different biological functions depending on its subcellular localization. The role of prohibitin 1 in liver cancer is controversial as it can be pro- or anti-tumorigenic. However, most of the studies to date have described prohibitin 1 primarily as a tumor suppressor in the liver. Its deficiency sensitizes the liver to cholestatic liver injury, non-alcoholic fatty liver disease, inflammatory insults, and cancer. Liver-specific Phb1-knockout mice spontaneously develop hepatocellular carcinoma, Phb1 heterozygotes are more susceptible to develop cholangiocarcinoma, and the majority of human hepatocellular carcinomas and cholangiocarcinomas have reduced prohibitin 1 expression. Consistent with a tumor suppressive role in the liver, prohibitin 1 negatively regulates proliferation in hepatocytes and human hepatocellular carcinoma and cholangiocarcinoma cell lines, and multiple oncogenic signaling pathways are activated when prohibitin 1 is deficient. Although best known as a mitochondrial chaperone, prohibitin 1 can protect the liver by mitochondrial-independent mechanisms. This review summarizes what’s known about prohibitin 1’s role in liver pathology, with the focus on hepatoprotection and carcinogenesis. Impact statement This review summarizes the last decades of research on PHB1 in liver pathobiology. PHB1 is a key player for liver health as it is hepatoprotective and tumor suppressive. We highlight the importance of PHB1’s subcellular localization, post-translational modifications, and interacting proteins as major determinants of PHB1 cytoprotective function and anti-tumor activity in the liver.


2015 ◽  
Vol 91 (5) ◽  
pp. 399-406 ◽  
Author(s):  
Xinna Wang ◽  
Jianmei Luo ◽  
Albert Wingnang Leung ◽  
Yajun Li ◽  
Hongwei Zhang ◽  
...  

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 903 ◽  
Author(s):  
Yang Hong

Establishing and maintaining cell polarity are dynamic processes that necessitate complicated but highly regulated protein interactions. Phosphorylation is a powerful mechanism for cells to control the function and subcellular localization of a target protein, and multiple kinases have played critical roles in cell polarity. Among them, atypical protein kinase C (aPKC) is likely the most studied kinase in cell polarity and has the largest number of downstream substrates characterized so far. More than half of the polarity proteins that are essential for regulating cell polarity have been identified as aPKC substrates. This review covers mainly studies of aPKC in regulating anterior-posterior polarity in the worm one-cell embryo and apical-basal polarity in epithelial cells and asymmetrically dividing cells (for example, Drosophila neuroblasts). We will go through aPKC target proteins in cell polarity and discuss various mechanisms by which aPKC phosphorylation controls their subcellular localizations and biological functions. We will also review the recent progress in determining the detailed molecular mechanisms in spatial and temporal control of aPKC subcellular localization and kinase activity during cell polarization.


BMC Cancer ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Huaqing Cui ◽  
Feng Wu ◽  
Yanling Sun ◽  
Guocai Fan ◽  
Qingming Wang

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0258312
Author(s):  
Jiangang Bi ◽  
Yusheng Guo ◽  
Qi Li ◽  
Liping Liu ◽  
Shiyun Bao ◽  
...  

Objective This study investigates the differential expression and the mechanism of long intergenic non-protein coding RNA (LINC) 01857 in hepatocellular carcinoma (HCC) proliferation and apoptosis. Methods LINC01857 expression in HCC tissues and cells was evaluated. In addition, gain-of and loss-of functions were carried out to assess HCC cell proliferation and apoptosis. After that, LINC01857 subcellular localization was predicted and verified. Additionally, the binding relations between LINC01857 and microRNA (miRNA)-197-3p and between miR-197-3p and anterior GRadient 2 (AGR2) were detected and confirmed. Besides, HCC cell proliferation and apoptosis were assessed after silencing LINC01857 or overexpressing AGR2. Next, levels of key factors in the AKT and ERK pathways were measured. Additionally, xenograft transplantation was also conducted to confirm the effect of LINC01857 in HCC. Results LINC01857 was overexpressed in HCC. Silencing LINC01857 leads to a blockage in HCC cell proliferation but improved apoptosis. LINC01857 could competitively bind to miR-197-3p and thus upregulate AGR2. miR-197-3p was poorly expressed in HCC, while AGR2 was overexpressed. Mechanistically, downregulated miR-197-3p or overexpressed AGR2 were observed to attenuate the effect of the LINC01857 knockdown on suppressing cell proliferation and enhancing apoptosis. Moreover, LINC01857 activated the AKT and ERK pathways through the manipulation of the miR-197-3p/AGR2 axis in HCC. Conclusion The results of this study indicated that LINC01857 was highly expressed in HCC, and it could improve HCC cell proliferation and reduce apoptosis via competitively binding to miR-197-3p, promoting AGR2 and upregulating the AKT and ERK pathways.


1993 ◽  
Vol 4 (12) ◽  
pp. 1307-1316 ◽  
Author(s):  
M Ziman ◽  
D Preuss ◽  
J Mulholland ◽  
J M O'Brien ◽  
D Botstein ◽  
...  

The Saccharomyces cerevisiae Cdc42 protein, a member of the Ras superfamily of low-molecular-weight GTP-binding proteins, is involved in the control of cell polarity during the yeast cell cycle. This protein has a consensus sequence (CAAX) for geranylgeranyl modification and is likely to be associated, at least in part, with cell membranes. Using cell fractionation and immunolocalization techniques, we have investigated the subcellular localization of Cdc42p. Cdc42p was found in both soluble and particulate pools, and neither its abundance nor its distribution varied through the cell cycle. The particulate form of Cdc42p could be solubilized with detergents but not with NaCl or urea, suggesting that it is tightly associated with membranes. An increase in soluble Cdc42p was observed in a geranylgeranyltransferase mutant strain (cdc43-2ts) grown at the restrictive temperature. In addition, Cdc42p from a cdc42C188S mutant strain (that has an alteration at the prenylation consensus site) was almost exclusively in the soluble fraction, suggesting that membrane localization is dependent on geranylgeranyl modification at Cys-188. Immunofluorescence and immunoelectron microscopy experiments demonstrated that Cdc42p localizes to the plasma membrane in the vicinity of secretory vesicles that were found at the site of bud emergence, at the tips and sides of enlarging buds, and within mating projections (shmoo tips) in alpha-factor-arrested cells. These results indicate that Cdc42p is localized to the bud site early in the cell cycle and suggest that this localization is critical for the selection of the proper site for bud emergence and for polarized cell growth.


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Michael J. LaQuaglia ◽  
James L. Grijalva ◽  
Kaly A. Mueller ◽  
Antonio R. Perez-Atayde ◽  
Heung Bae Kim ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document