A group of interacting polarity regulators including PAR-3, PAR-6 and atypical protein kinase C. Its organization links cortical domains to junctional and morphogenetic behaviour.

Coordinated asymmetry within the plane of a tissue, distinct from the apical-basal axis. Not every case of planar polarization uses the same molecular pathway.

Growth concentrated at a selected part of the biological cell surface. Spatial selection can be controlled at transport, vesicle docking or fusion rather than only by directed vesicle motion.

The nuclear lamina is a network of lamin intermediate-filament proteins associated with the inner face of the nuclear envelope in many animal cells. It supports nuclear architecture and connects the envelope with chromatin. During typical open mitosis, regulated phosphorylation promotes lamina disassembly, allowing nuclear-envelope breakdown; reassembly accompanies formation of daughter nuclei. The nuclear lamina is therefore a dynamic structural system rather than an inert shell. ^[ref]

Nuclear retention is persistence of a molecule inside the cell nucleus through binding, assembly or restricted export. For example, an incompletely processed RNA can remain nuclear while a mature transcript is exported. Nuclear enrichment can arise through faster import, slower export or binding to a nuclear component, so a static image alone does not identify the underlying rate change. Nuclear retention is a localization mechanism distinct from synthesis occurring only in the nucleus. ^[ref]

In collective cell migration, neighbouring biological cells move with coordinated trajectories while retaining interactions that influence their motion. Mechanical coupling, contact-dependent signals and soluble cues can each contribute. A coherent group need not consist of identically behaving cells: leaders and followers may perform different roles.

A lamellipodium is a broad, thin, actin-rich protrusion at a cell edge. Actin polymerization pushes the cell membrane, but net advance also depends on mechanical coupling to the environment.

A membrane bleb is a rounded protrusion formed when the cell membrane locally detaches from or loses support by the cell cortex. Pressure expands the initially cortex-poor region; cortical reassembly can then stabilize or retract it.

Chemokinesis is a change in motility associated with a chemical stimulus without a directional bias toward or away from its source. Measure speed and persistence separately from directional chemotaxis.

Durotaxis is biased cell migration associated with spatial variation in substrate stiffness. Distinguish a directional bias from changes in speed, attachment or survival on different substrates.

Haptotaxis is directed cell migration along spatial variation of an immobilized adhesive or guidance cue. It differs from guidance by a soluble chemoattractant field.

Contact guidance is a directional influence of physical structures, such as aligned fibres or grooves, on cell migration. It can organize trajectories without an imposed soluble concentration gradient.

Displacement of cells with bulk tissue motion. Subtracting the surrounding flow is needed to distinguish autonomous crawling from passive transport.

A membrane nanodomain is a small region with locally differing composition or molecular organization. Its size, lifetime and physical origin require measurement; detergent resistance alone does not demonstrate a pre-existing domain in a living membrane.

homeoviscous adaptation changes membrane composition in response to conditions such as growth temperature, helping preserve useful membrane dynamics. The original Escherichia coli study measured temperature-dependent fatty-acid changes and membrane-lipid viscosity by spin labeling.^[ref]

Membrane shape affects the energetic cost and geometry of a bud, neck or protrusion. Proteins, lipid composition and mechanical forces can change curvature; curvature alone does not perform the topological reconnection required for membrane fusion or membrane fission.

Membrane fusion joins initially separate lipid bilayers, changing connections between membrane compartments. It requires controlled rearrangement of both leaflets while avoiding uncontrolled leakage.

Membrane fission separates a connected membrane into distinct components, for example by severing a vesicle neck. Bending a membrane into a bud without severing that neck is not yet fission.

The lipid divide is the contrast between characteristic archaeal membrane lipids and characteristic bacterial/eukaryotic membrane lipids, including glycerol stereochemistry and ether versus ester linkages. It constrains hypotheses for eukaryotic origins without uniquely determining the sequence of ancestral membrane changes.

GLUT2 is a facilitative glucose transporter with important roles in hepatocytes and in the classical rodent beta-cell model. It supports transport down a concentration gradient and should not be assumed to be the predominant human beta-cell glucose transporter.