Inositol-trisphosphate 3-kinase B

Inositol-trisphosphate 3-kinase B (ITPKB) is a phosphotransferase that catalyzes the conversion of inositol 1,4,5-trisphosphate (InsP3) to inositol 1,3,4,5-tetrakisphosphate, a critical step in intracellular calcium signaling and homeostasis (UniProt: P27987). The enzyme participates in phosphoinositide signaling cascades that regulate cellular calcium dynamics across multiple tissues.

ITPKB is ubiquitously expressed and functions within the broader inositol phosphate metabolism pathway controlling calcium mobilization from intracellular stores. No baseline disease associations are documented in UniProt, though dysregulation of inositol signaling has been implicated in several neurological contexts.

ITPKB is associated with Alzheimer's Disease in this dataset. Analysis of post-mortem human AD brain tissue versus age-matched controls identified ITPKB as significantly elevated, with a mean log2 fold-change of 0.68 across one subcellular fraction (Chaparral AD proteomics). This upregulation suggests potential involvement in AD-associated calcium dysregulation or compensatory signaling alterations in affected brain tissue.