Mammalian pumilio proteins control cellular morphology, migration, and adhesion
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Published on: July 27, 2022
Erin L Sternburg1, Jordan J Lillibridge1, Rattapol Phandthong1
1Department of Molecular, Cell and Systems Biology, University of California at Riverside, Riverside, CA, 92521, USA.
Abstract:
Pumilio proteins are RNA-binding proteins that control mRNA translation and stability by binding to the 3' UTR of target mRNAs. Mammals have two canonical Pumilio proteins, PUM1 and PUM2, which are known to act in many biological processes, including embryonic development, neurogenesis, cell cycle regulation and genomic stability. Here, we characterized a new role of both PUM1 and PUM2 in regulating cell morphology, migration, and adhesion in T-REx-293 cells, in addition to previously known defects in growth rate. Gene ontology analysis of differentially expressed genes in PUM double knockout (PDKO) cells for both cellular component and biological process showed enrichment in categories related to adhesion and migration. PDKO cells had a collective cell migration rate significantly lower than that of WT cells and displayed changes in actin morphology. In addition, during growth, PDKO cells aggregated into clusters (clumps) due to an inability to escape cell-cell contacts. Addition of extracellular matrix (Matrigel) alleviated the clumping phenotype. Collagen IV (ColIV), a major component of Matrigel, was shown to be the driving force in allowing PDKO cells to monolayer appropriately, however, ColIV protein levels remained unperturbed in PDKO cells. This study characterizes a novel cellular phenotype associated with cellular morphology, migration, and adhesion which can aid in developing better models for PUM function in both developmental processes and disease.
Insights
Pumilio proteins PUM1 and PUM2 regulate cell adhesion and migration. Disrupting these Pumilio proteins (PDKO) in cells impairs their ability to migrate and form monolayers, revealing a new role for PUM proteins.
Area of Science:
- Molecular Biology
- Cell Biology
- Developmental Biology
Background:
- Pumilio proteins (PUM1 and PUM2) are key RNA-binding proteins regulating mRNA translation and stability.
- These proteins are involved in critical biological processes such as embryonic development, neurogenesis, cell cycle, and genomic stability.
Purpose of the Study:
- To investigate a novel function of PUM1 and PUM2 in regulating cell morphology, migration, and adhesion.
- To characterize the cellular phenotype of cells lacking both PUM1 and PUM2 (PDKO cells).
Main Methods:
- Gene ontology analysis of differentially expressed genes in PDKO cells.
- Assessment of collective cell migration rates and actin morphology.
- Evaluation of cell aggregation and response to extracellular matrix components like Matrigel and Collagen IV.
Main Results:
- PDKO cells exhibited significantly reduced collective cell migration rates and altered actin morphology.
- PDKO cells formed clusters due to impaired cell-cell contact escape, indicating defective adhesion and migration.
- Extracellular matrix, particularly Collagen IV, partially rescued the monolayer formation defect, despite unperturbed Collagen IV levels.
Conclusions:
- PUM1 and PUM2 play a critical, previously unrecognized role in regulating cell morphology, migration, and adhesion.
- The findings provide new insights into Pumilio protein function in cellular processes and disease modeling.
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