TANGO1 is an ER-exit-site organizer that connects lumenal cargo handling with cytoplasmic transport machinery. Its involvement in collagen export does not require that every collagen carrier have one fixed geometry.

PDZD8 contributes to mammalian ER–mitochondrial contact organization and calcium handling in studied cellular contexts. Contact morphology, organelle potential and calcium-store loading need separate measurements when interpreting depletion.

Sca2 is a rickettsial surface protein with actin-assembly activity in studied species. Purified-component assays reveal formin-like mechanisms, while cellular experiments test their contribution to movement and spread.

A genetically encodable protein that emits fluorescence after appropriate excitation. Fusion constructs can label cellular structures, but expression and illumination must be controlled for effects on the process being observed.

A receptor used as a marker of active stem-cell biological populations in several epithelial settings. Reporter expression must be distinguished from functional evidence that a cell sustains long-term tissue renewal.

A family of extracellular proteins that potentiate Wnt signalling in appropriate receptor contexts and help sustain stem-cell activity in intestinal culture systems.

A protein whose perturbation has been used to generate prospective loser cells in Drosophila cell-competition experiments.

A stress-responsive regulatory protein encoded by TP53. Different mutant alleles can alter tissue competition in different ways; a mutation is not an invariant measure of competitive fitness.

A protein participating in cell adhesion and canonical Wnt signalling. Its localization and molecular partners affect which function is being measured.

A small GTPase regulating cellular organization. Its contributions to surface trafficking, polarity and spindle positioning depend on the epithelial model.

A polarity scaffold associated with epithelial junction organization. Its fly counterpart is Bazooka.

By binding other polarity components, it helps organize where a signalling complex assembles. The shared relationship between PAR-3 and Bazooka is useful for comparing systems, while exact localization and partner requirements depend on species and cell type. ^[ref]

A Drosophila PAR-3-family polarity scaffold. Its anisotropic cortical distribution can participate in coordinating epithelial neighbour exchange.

An epithelial apical-domain regulator. Its activity must be balanced with other polarity regulators to control apical membrane extent and epithelial tube dimensions.

A Drosophila polarity regulator whose interaction with Crumbs-associated activity contributes to epithelial tube-size control.

A Drosophila septate-junction-associated protein with structural and morphogenetic functions. Tube-size control and luminal secretion can be experimentally separable outputs.

A secreted matrix-modifying protein involved in organizing the Drosophila tracheal lumen. Testing its secretion helps distinguish matrix defects from parallel polarity-dependent tube-size defects.

An epithelial polarity regulator with additional roles in growth control and tissue organization. Mutant phenotypes need not follow the same downstream route as those of every other basolateral regulator.

Munc18 denotes a Sec1-Munc18 family of proteins that regulate SNARE-dependent membrane fusion. Different isoforms interact with particular syntaxin-associated pathways; Munc18-1 is prominent in neuronal secretion, while Munc18c participates in other trafficking systems. Binding to a syntaxin and promoting productive fusion are separable activities. Reconstitution experiments test how these regulators favour assembly of the appropriate fusion machinery. ^[ref]

MT1-MMP, also called MMP14, is a membrane-associated metalloprotease involved in remodelling the extracellular matrix. Surface delivery concentrates proteolytic activity at particular cellular locations, linking vesicle trafficking to matrix interactions. Altered total protein abundance and altered delivery to the surface are different routes to changing extracellular activity. This distinction matters when relating a trafficking perturbation to cell invasion. ^[ref]

A factor accelerating release of bound guanine nucleotide from a target protein, permitting reloading from the free pool. It does not phosphorylate bound GDP into GTP.