PT  - JOURNAL ARTICLE
AU  - S.M.A. de Man
AU  - G. Zwanenburg
AU  - M.A. Hink
AU  - R. van Amerongen
TI  - Quantitative live-cell imaging yields novel insight into endogenous WNT/CTNNB1 signaling dynamics
AID  - 10.1101/2020.05.28.120543
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.05.28.120543
4099  - http://biorxiv.org/content/early/2020/05/28/2020.05.28.120543.short
4100  - http://biorxiv.org/content/early/2020/05/28/2020.05.28.120543.full
AB  - WNT/CTNNB1 signaling regulates tissue development and homeostasis in all multicellular animals. Multiple aspects of the underlying molecular mechanism remain poorly understood and critical information on endogenous WNT/CTNNB1 signaling dynamics is missing. Here we combine CRISPR/Cas9-mediated genome editing and quantitative live-cell microscopy to measure diffusion characteristics of fluorescently tagged, endogenous CTNNB1 in human cells with high spatiotemporal resolution. State-of-the-art functional imaging reveals that both in the absence and presence of WNT, a substantial fraction of CTNNB1 resides in slow-diffusing complexes in the cytoplasm and that WNT stimulation changes their identity. We also measure the concentration of complexed and free CTNNB1 in both the cytoplasm and the nucleus before and after WNT stimulation, and use these parameters to build a minimal computational model of WNT/CTNNB1 signaling. Our work reveals that WNT regulates the dynamic distribution of CTNNB1 across different functional pools by modulating the destruction complex, nucleocytoplasmic shuttling and nuclear retention.Competing Interest StatementThe authors have declared no competing interest.