FGF23

Entity resolution

Record the evidence identifying the entity as FGF23 protein rather than DNA, RNA or another FGF.

1. Does this record concern FGF23 protein, its encoding gene or its transcript? boundary
2. Which accession or sequence evidence establishes FGF23 protein identity? definition

Sequence provenance

Attach species and construct boundaries to molecular and experimental claims.

1. Which species and versioned protein sequence define the residue numbering? provenance
2. Which substitutions, truncations or tags distinguish this material from endogenous FGF23? definition

Form assignment

Record experimentally supported residue boundaries and distinguish secretory maturation from subsequent fragmentation.

1. Does the material retain its signal peptide, represent mature intact FGF23 or contain cleavage fragments? definition
2. Which sequence, mass-spectrometric or immunoblot evidence establishes the assigned form? measurement

Cleavage susceptibility

Distinguish measured modification states and cleavage behavior from predictions based on enzyme expression. [Primary processing study](https://pubmed.ncbi.nlm.nih.gov/26746780/)

1. Which glycosylation or phosphorylation sites were measured on this FGF23 preparation? measurement
2. What evidence connects its sequence or modifications to cleavage under the stated conditions? provenance

Production evidence

Keep transcript expression, intracellular protein and released FGF23 as distinct observations.

1. Which cells or tissues are evidenced to produce FGF23 in this organism and condition? provenance
2. Was production inferred from RNA, measured as intracellular protein or demonstrated by secretion? measurement

Concentration drivers

Separate evidence for synthesis, cleavage and removal; human renal sampling provides one approach to studying clearance. [Primary renal clearance study](https://pmc.ncbi.nlm.nih.gov/articles/PMC9177785/)

1. Which compartment and sampling time does the FGF23 concentration describe? measurement
2. What evidence distinguishes increased secretion from changed cleavage or reduced clearance? boundary

Signaling attribution

Require a defined responding system and controls before attributing activity to FGF23.

1. Which FGFR and alpha-Klotho conditions were established in the responding cells? measurement
2. Which inhibition, depletion or rescue controls attribute the response specifically to FGF23? provenance

Functional endpoints

Record the measured endpoint and timing instead of treating circulating FGF23 as a direct measurement of physiological effect.

1. Which renal phosphate-handling or vitamin D endpoint changed after the defined FGF23 exposure? measurement
2. What separates an FGF23-mediated effect from concurrent changes in kidney function, PTH or mineral intake? boundary

Detected molecular population

C-terminal immunoreactivity must not be labeled fragment-only concentration; intact assays and C-terminal assays recognize different molecular populations. [Primary assay study](https://link.springer.com/article/10.1007/s00198-012-2029-3)

1. Does the assay detect intact FGF23, intact plus C-terminal fragments or another defined target? definition
2. Which epitope and cross-reactivity evidence supports that analyte definition for this species? provenance

Calibration and specimen

Keep units, calibrator, assay platform and specimen history attached to the result; do not subtract unlike assay values to estimate fragments.

1. What units, calibrator, quantification limits and specimen conditions apply to this result? measurement
2. What validation permits comparison, conversion or combination with the other FGF23 measurements? action

Contextual meaning

An assay reference interval and physiological appropriateness are separate assessments; neither alone establishes a disease or treatment indication.

1. Which simultaneous phosphate, kidney function, vitamin D and PTH observations are needed for this interpretation? measurement
2. Does the evidence support association, a mechanistic explanation or only a request for further investigation? boundary

Preparation acceptance

Assess identity, intactness and activity in relation to the proposed experiment rather than relying on the reagent label.

1. Which identity, cleavage, purity and potency measurements qualify this lot for the intended experiment? measurement
2. Which controls distinguish FGF23 activity from tag effects, contaminants or accompanying fragments? action

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 FGF23 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 FGF23 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 FGF23 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 FGF23 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 FGF23 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 FGF23 this model covers, and on what evidence? provenance