cellpolarisering

Cellpolarisering, or cell polarization, refers to the process by which a cell establishes and maintains functional and structural asymmetry, resulting in distinct domains with specialized roles. This organization enables directed movement, asymmetric division, and the coordinated formation of tissues during development. Polarization is dynamic and context-dependent, often reversible as cells respond to cues from their environment.

The process is orchestrated by conserved polarity pathways that coordinate the cytoskeleton and membrane identity. In many animal cells, PAR protein complexes (such as PAR-3, PAR-6 and aPKC) interact with Rho family GTPases (Cdc42, Rac1, RhoA) to orient the actin cytoskeleton and microtubules. Phosphoinositide lipids, especially PIP2 and PIP3, help define membrane domains and recruit polarity effectors. External cues like chemokines, extracellular matrix composition, and mechanical signals can initiate polarity, which then becomes stabilized by feedback loops.

Polarity manifests in different forms. Epithelial cells show apical–basal polarity with distinct apical surfaces and basolateral membranes. Migrating cells exhibit front–rear polarity with a leading edge and trailing end. In development and stem cell biology, asymmetric cell division generates daughter cells with different fates, while neurons polarize to form axons and dendrites. Examples include immune cell chemotaxis, wound healing, and neural development across species.

Disruptions in cell polarity are linked to disease, notably cancer metastasis and congenital disorders. Researchers study polarization through live-cell imaging, genetic perturbations of polarity regulators, and perturbation of signaling pathways, providing insight into tissue organization and regenerative medicine. The term cellpolarisering is used in Danish-language contexts to denote this phenomenon.