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Automated Imaging and Analysis for the Quantification of Fluorescently Labeled Macropinosomes
Published on: August 24, 2021
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Wnt, GSK3, and Macropinocytosis
Nydia Tejeda-Muñoz1, Edward M De Robertis2
1Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
Sub-Cellular Biochemistry
|April 5, 2022
Summary
Wnt signaling sustains nutrient acquisition via macropinocytosis by inhibiting GSK3, a process crucial for cell growth and potentially cancer progression. This pathway involves the ESCRT machinery and multivesicular bodies.
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Biology
Background:
- Canonical Wnt signaling primarily regulates nuclear beta-catenin.
- Emerging evidence highlights Wnt pathway's broader roles beyond beta-catenin.
- Macropinocytosis, a nutrient uptake process, is regulated by growth factor signaling.
Purpose of the Study:
- To review the regulation of macropinocytosis by Wnt growth factor signaling.
- To elucidate the mechanisms by which Wnt signaling sustains nutrient acquisition.
- To explore the role of GSK3 and ESCRT machinery in Wnt-induced macropinocytosis.
Main Methods:
- Review of existing literature on Wnt signaling, macropinocytosis, and cellular transport.
- Analysis of the role of GSK3 inhibition and ESCRT machinery in Wnt-induced macropinocytosis.
- Examination of Wnt signaling's impact on nutrient acquisition and lysosomal acidification.
Main Results:
- Wnt signaling promotes sustained macropinocytosis for nutrient acquisition.
- Endocytosis of Wnt receptor complexes triggers GSK3 sequestration via ESCRT and MVBs.
- GSK3 inhibition alone can trigger macropinocytosis, independent of new protein synthesis.
- Wnt-induced macropinocytosis and lysosomal acidification require the ESCRT machinery.
- Mutations in APC and Axin1 lead to increased macropinocytosis in cancer cells.
Conclusions:
- Wnt signaling plays a significant role in regulating macropinocytosis for sustained nutrient uptake.
- The ESCRT machinery and GSK3 inhibition are key components of Wnt-mediated macropinocytosis.
- Dysregulation of this pathway, particularly in cancer, contributes to aberrant macropinocytosis.
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