BGLAP

BGLAP, or bone gamma-carboxyglutamate protein, is a gene that encodes osteocalcin, a small non-collagenous protein produced by osteoblasts in bone. Osteocalcin is a secreted, vitamin K–dependent protein that becomes modified by gamma-carboxylation of glutamate residues, a process essential for its calcium-binding capacity within the bone matrix.

In bone, osteocalcin binds to hydroxyapatite, contributing to the mineralization process and the structural integrity of the bone matrix. The carboxylated form of osteocalcin is predominantly associated with bone, while the undercarboxylated form is released into circulation. Circulating osteocalcin levels reflect bone turnover and are influenced by vitamin K status, age, sex, and hormonal factors. Serum osteocalcin is often used as a biomarker of bone formation in research and, to a lesser extent, in clinical practice, though its interpretation can be affected by dietary vitamin K and other variables.

Beyond its structural role, osteocalcin has been studied for potential endocrine functions. In animal models, undercarboxylated osteocalcin has been proposed to influence energy metabolism by stimulating insulin production and sensitivity and affecting adipose tissue. In humans, while associations between osteocalcin and metabolic parameters have been reported, the evidence for a clear hormonal role remains inconclusive.

Genetically, BGLAP is expressed mainly in osteoblast-lineage cells and is regulated by factors involved in bone formation and mineralization. Variants in or regulation of BGLAP can influence osteocalcin levels and bone metabolism, with research continuing to clarify connections to bone health and metabolic processes.

In summary, BGLAP encodes osteocalcin, a vitamin K–dependent bone protein central to mineralization and bone turnover, with ongoing research into broader metabolic and clinical implications.