PIP5K1B encodes phosphatidylinositol-4-phosphate 5-kinase type 1 beta, an enzyme that catalyzes the phosphorylation of phosphatidylinositol 4-phosphate (PI4P) to generate phosphatidylinositol-4,5-bisphosphate (PIP2), a critical lipid second messenger 1. PIP5K1B plays essential roles in cytoskeletal organization and cellular signaling, with decreased PIP5K1B expression causing actin cytoskeleton destabilization and delayed cell spreading 1. The enzyme functions coordinately with PIP5K1A in spermatogenesis, where both isoforms are required for maintaining sperm morphology and number 2. PIP5K1B activity is negatively regulated through phosphorylation at Ser413 by AMPK and PKC in response to oxidative stress and energy restriction, resulting in decreased PIP2 synthesis 3. Disease relevance includes Friedreich's ataxia, where GAA repeat expansions cause cis-silencing of PIP5K1B, contributing to cytoskeletal anomalies observed in patient cells 1. PIP5K1B also serves as a diagnostic biomarker for periodontitis 4 and interacts with LRRC8A to regulate colon cancer metastasis through the PIP2 pathway 5. These findings establish PIP5K1B as a key regulator of cellular membrane dynamics with significant implications for neurological disease and cancer.