DMP1 review notes (2026-10-10)

Deep research: the first just deep-research-falcon human DMP1 call timed out (600 s); a falcon report
(DMP1-deep-research-falcon.md, 2026-10-10) was nonetheless written later and agrees with the manual work below:
it concludes DMP1 is a "regulator of bone and tooth matrix mineralization" that restrains osteocytic FGF23 by an
incompletely understood mechanism. Literature work was done manually via PubMed and the cached publications/.

Function

• Acidic SIBLING-family matrix phosphoprotein of dentin/bone; cloning paper describes "a matrix-associated
  acidic phosphoprotein, with a potentially high calcium ion binding capacity" PMID:8509401.
• Recombinant DMP1 binds calcium and nucleates apatite: "recombinant DMP1 (rDMP1) possesses calcium-binding
  ability under physiological conditions" and "DMP1 could be considered as a nucleator for apatite deposition
  in vitro" PMID:12952204.
• Phosphorylation/cleavage state matters: "in its native form, DMP1 inhibits mineralization, but when cleaved
  or dephosphorylated, it initiates mineralization" PMID:14769788.
• Phosphorylated by FAM20C: "Fam20C phosphorylated OPN, MEPE, and DMP1 in a time-dependent manner" PMID:22582013.
• Proposed nuclear role (single group): "In the nucleus, DMP1 acts as a transcriptional component for
  activation of osteoblast-specific genes like osteocalcin" PMID:12615915 - kept non-core.

Disease (ARHR1)

• "absence of DMP1 results in defective osteocyte maturation and increased FGF23 expression" PMID:17033621.
• "suggesting that DMP1 may regulate FGF23 expression" PMID:17033625.
• The FGF23-suppressing role is real at the physiological level but the molecular mechanism is unknown, so it
  is a suggested question rather than a core function / GO process assertion.

Curation decisions

• Ossification rows -> MODIFY to bone mineralization (GO:0030282).
• ECM organization (IBA/IEA) -> MARK_AS_OVER_ANNOTATED; DMP1 regulates mineral, not matrix assembly.
• Core function: calcium ion binding (GO:0005509) in bone/dentin mineralization, extracellular matrix.
• Alignment with dismech Autosomal_Recessive_Hypophosphatemic_Rickets_1: molecular node now carries calcium
  ion binding DECREASED; downstream nodes use bone mineralization / dentin mineralization DECREASED.