claudins

Member assignment

Record the evidence needed to assign a protein to the claudin family and resolve its name.

1. Which curated accession, species and sequence support the proposed claudin member assignment? provenance
2. Does the supplied name identify the whole family, one paralogue, an orthologue group or an unresolved historical label? definition

Form-specific identity

Establish which sequence and preparation features constrain interpretation.

1. Which isoform, substitutions, tags, truncations or post-translational modifications distinguish this form from the reference sequence? definition
2. For an isolated preparation, what evidence establishes identity, purity and the detergent, lipid or membrane environment? measurement

Structural region assignment

Distinguish experimentally established structure from sequence-based topology predictions.

1. Which transmembrane, extracellular and cytoplasmic regions are established for this member, and by what method? provenance
2. Which proposed binding epitopes or interaction motifs are accessible in the membrane state under consideration? boundary

Assembly compatibility

Require direct evidence for partner compatibility and functional junctional incorporation.

1. Which same-membrane and opposing-membrane claudin interactions are demonstrated rather than inferred from coexpression? provenance
2. What imaging, interaction or structural evidence establishes junctional assembly and scaffold association for this molecular form? measurement

Permeation profile

Frame permeability as a measured profile rather than a binary barrier label.

1. Which ions or solutes were tested, and what permeability coefficients, selectivity ratios or fluxes were measured? measurement
2. Under which ionic gradients, pH, temperature and epithelial or endothelial conditions does the reported profile hold? boundary

Member-specific barrier contribution

Separate claudin-dependent effects from changes in cell viability, junction integrity or other transport routes.

1. Which matched controls, loss-of-function comparisons or rescue experiments support attribution to this claudin? provenance
2. Do resistance, tracer and ion-selectivity measurements distinguish selective permeation from nonspecific leakage or transcellular transport? measurement

Context-resolved presence

Keep transcript detection, protein abundance and junctional localisation distinct.

1. In which species, tissue, cell type and developmental or experimental state was this claudin detected? boundary
2. Does the evidence measure RNA, total protein, surface protein or junctional protein, and at what resolution? measurement

State-change mechanisms

Connect observed claudin transitions to evidenced triggers and downstream readouts.

1. Which stimulus or modification is associated with altered claudin trafficking, junctional retention or degradation? provenance
2. What time course and reversibility measurements connect the molecular transition to a change in localisation or permeability? measurement

Assay specificity

Require validation appropriate to the member, species, specimen and assay format.

1. What knockout, orthogonal assay or cross-reactivity evidence validates detection of the intended claudin? provenance
2. Could fixation, permeabilisation, tagging or epitope masking change the apparent abundance or localisation? boundary

Interpretable intervention

Define the intended target state, measurable outcome and controls needed for a supported action.

1. Which genetic alteration or binding reagent can test the proposed claudin function in this system, and what establishes target engagement? action
2. Which controls distinguish direct claudin effects from compensatory family-member expression, cytotoxicity or general junction disruption? measurement

Check these first

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these check these first hold for the sense of claudins this model covers, and on what evidence? provenance

Kinds and varieties

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these kinds and varieties hold for the sense of claudins this model covers, and on what evidence? provenance

Identifiers and schemes

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these identifiers and schemes hold for the sense of claudins this model covers, and on what evidence? provenance

Real-world use

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these real-world use hold for the sense of claudins this model covers, and on what evidence? provenance

Typical measurements

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these typical measurements hold for the sense of claudins this model covers, and on what evidence? provenance

Failure modes and hazards

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these failure modes and hazards hold for the sense of claudins this model covers, and on what evidence? provenance

Neighbouring kinds and how to tell them apart

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these neighbouring kinds and how to tell them apart hold for the sense of claudins this model covers, and on what evidence? provenance