How to assess Wnt activation in vivo
The most universal outputs for wnt signaling are: axin2 expression, best measured in the axin2-LacZ mice, and beta-catenin nuclear staining.
Dear Dr. Nusse,
My name is Elizabeth Amadei, and I am a graduate student in biomedical engineering at Georgia Tech. I am working on a project to develop a mathematical model of the Wnt pathway. I am specifically interested in the role of Suppressor of Fused (SUFU) on Wnt signaling. Meng et al. (2001) propose that Sufu binds to B-catenin and exports it from the nucleus. I noticed that the models posted on this webpage do not include SUFU. Is there a reason for this? Thank you for your help,
Meng X, Poon R, Zhang X, Cheah A, Ding Q, Hui CC, Alman B (2001) Suppressor of fused negatively regulates beta-catenin signaling. J Biol Chem. 2001 Oct 26;276(43):40113-9.
Thanks. By necessity, we cannot include all of the possible components of Wnt signaling in our diagrams, as there might be ~100 claims. Those components that have been established by multiple groups and papers are given preference.
Hi, We are trying to assess Wnt activity in patient material (tumor biopsies). We`ve got material to perform qPCR and IHC etc. Preliminary experiments have show that axin2 expression alone might not be the best parameter. Do you guys have any recommendation? Maybe look at multiple parameter?
Thanks for the help.
Thanks, Dr. Nusse. That's the exact information I was looking for.
I work in the department of immunology at M.D. Anderson Cancer Center. I have generated a mouse model that reproduces the features observed in colitis-associated colorectal cancer. This mouse develops severe inflammation in the colon that leads to adenocarcinoma in few weeks. I did beta catenin staining in mutant colon samples and observed an extraordinary accumulation of this protein in the nucleus as compared with the WT (mainly in the cell membrane and cytoplasm); however, I did western blotting for TCF4/LEF and found little change in both proteins. My question is: how can I assess the disruption of the degradation complex? My hypothesis is that the knocked out protein is somehow stabilizing the complex. Is it possibe to analyze the dissociation of APC/Axin/LRP/DSH/Frz, separately? Will the dissociation serve as a read out to compare the mutant against the WT cells? I exposed deficient cells to LiCl, as a non-specific GSK-b inhibitor, to activate Wnt. The deficient and WT cells showed accumulation of beta catenin in the nucleus.
Thanks for your attention. I am not in the Wnt signaling field and I will really appreciate any help.
Nahum Puebla, Ph.D.
Department of Immunology
M.D. Anderson Cancer Center
7455 Fannin. Box 902.
Houston, TX. 77054