Cell polarity is implicated in differentiation, proliferation and morphogenesis of unicellular and multicellular organisms. Cell polarity relies on the asymmetric organization of cellular components and structures, and the establishment and maintenance of cell polarity involves many processes including signalling cascades, membrane trafficking events and cytoskeletal dynamics, all of which need to be coordinated in a highly regulated manner. Dysregulation of cell polarity can cause developmental disorders and cancer.
This special Focus aims to capture the status quo of cell polarity research in a range of different systems by dissecting the underlying principles. The Focus include 5 Review articles authored by leaders in the field, and the topics range from organelle positioning, cytoskeletal dynamics and mechanisms of protein sorting, targeting and distribution in polarized cells, to crosstalk between small GTPases and polarity proteins, and the mechanisms that coordinate the assembly of cells into polarized tissues.
Research Highlights
Cell polarity: Sticky poles
doi:10.1038/nrm2534
Nature Reviews Molecular Cell Biology 9, 823
In brief
Cell polarity | Cell polarity | Protein degradation | PDF (138 KB)
p825 | doi:10.1038/nrm2542
Nature Reviews Molecular Cell Biology 9, 825
Cell polarity: Numb localization nailed
doi:10.1038/nrm2538
Nature Reviews Molecular Cell Biology 9, 828
Reviews
Coordinated protein sorting, targeting and distribution in polarized cells
Ira Mellman & W. James Nelson
doi:10.1038/nrm2525
Nature Reviews Molecular Cell Biology 9, 833
Polarization requires the coordinated interaction of three machineries that modify the basic mechanisms of intracellular protein trafficking and distribution. The integration of these mechanisms into a complex and dynamic network is crucial for normal tissue function and is often defective in disease states.
Crosstalk between small GTPases and polarity proteins in cell polarization
Sandra Iden & John G. Collard
doi:10.1038/nrm2521
Nature Reviews Molecular Cell Biology 9, 846
Conserved proteins of the partitioning defective (PAR), Scribble and Crumbs complexes guide the establishment of cell polarity in various organisms. Small GTPases have also been implicated in cell polarization. How do the polarity complexes and the small GTPases coordinate cellular polarization in different cell types?
Beyond polymer polarity: how the cytoskeleton builds a polarized cell
Rong Li & Gregg G. Gundersen
doi:10.1038/nrm2522
Nature Reviews Molecular Cell Biology 9, 860
Actin and microtubules are dynamic polar polymers that are well suited for providing the structural basis for cell polarity. The actin cytoskeleton generally drives symmetry breaking, whereas microtubules control polarity maintenance. These events are coordinated by bidirectional crosstalk between actin and microtubules.
Organelle positioning and cell polarity
Michel Bornens
doi:10.1038/nrm2524
Nature Reviews Molecular Cell Biology 9, 874
The positioning of each cytoskeletal or membrane organelle must be coupled to that of other organelles in order to contribute efficiently to cell polarity. The non-random positioning of organelles is preserved and transmitted through cell division.
From cells to organs: building polarized tissue
David M. Bryant & Keith E. Mostov
doi:10.1038/nrm2523
Nature Reviews Molecular Cell Biology 9, 887
Tissue structures and shapes can be formed by organizing groups of cells into different polarized arrangements and by coordinating their polarity in space and time. Conserved design principles that underlie tissue polarity are emerging from studies of model organisms and tissues.
