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Paxillin is required for cell-substrate adhesion, cell sorting and slug migration during Dictyostelium development
Tanya Bukharova1, Tanya Bukahrova, Gertrud Weijer
1Wellcome Trust Biocentre, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
Journal of Cell Science
|September 13, 2005
Summary
Dictyostelium PaxB protein is crucial for cell adhesion and multicellular development. Loss of PaxB impairs cell sorting, migration, and fruiting body formation, highlighting its essential role in development.
Area of Science:
- Cell Biology
- Developmental Biology
- Biochemistry
Background:
- Paxillin proteins regulate focal adhesions, influencing cell movement and substrate interactions.
- PaxB is a Dictyostelium discoideum paxillin homologue with conserved domains but lacking key tyrosine residues for SH2-binding.
- PaxB expression peaks during Dictyostelium slug formation, suggesting a role in multicellular development.
Purpose of the Study:
- To investigate the function of the Dictyostelium paxillin homologue, PaxB, in cell adhesion and multicellular development.
- To characterize the localization and dynamics of PaxB during Dictyostelium development.
- To determine the role of PaxB in cell sorting, migration, and morphogenesis.
Main Methods:
- Generated a paxB-gfp knockin strain to visualize PaxB localization and focal adhesion dynamics.
- Created paxB- null mutant strains to assess developmental phenotypes.
- Analyzed cell adhesion, aggregation, multicellular development, cell type proportioning, cell sorting, slug migration, and fruiting body formation in mutant strains.
- Investigated the role of a JNK phosphorylation site and the relationship with the related gene Lim2 (paxA).
Main Results:
- PaxB localizes to focal adhesions and filopodial tips during Dictyostelium development.
- paxB- strains exhibit reduced cell adhesion, impaired multicellular development from the mound stage, and defects in cell sorting and fruiting body formation.
- Mutation of a conserved JNK phosphorylation site did not significantly affect migration or morphogenesis.
- PaxB does not function redundantly with Lim2 (paxA), and evidence suggests PaxB acts upstream of Lim2.
Conclusions:
- PaxB is essential for Dictyostelium multicellular development, regulating cell adhesion, migration, and morphogenesis.
- PaxB's function is distinct from Lim2, with PaxB potentially acting upstream in a developmental pathway.
- The study elucidates PaxB's critical role in coordinating cellular behaviors during Dictyostelium development.