PIP5K1A

PIP5K1A (phosphatidylinositol-4-phosphate 5-kinase type 1 alpha) is a type I phosphatidylinositol phosphate kinase that phosphorylates phosphatidylinositol 4-phosphate (PI4P) to generate phosphatidylinositol 4,5-bisphosphate (PI(4,5)P₂), a central lipid messenger that regulates cytoskeleton organization, vesicular trafficking, cellular morphogenesis, signaling, and gene expression^[1][2]. Mechanistically, PIP5K1A contributes to localized PI(4,5)P₂ synthesis, and PIP kinase-dependent production of this lipid is tightly coupled to effector regulation, thereby defining signaling specificity at the plasma membrane and supporting phosphoinositide 3-kinase (PI3K) pathway activity and other PI(4,5)P₂-dependent cellular processes^[2][3]. In disease-relevant contexts, alterations in phosphoinositide kinase expression and signaling have been linked to cancer, immune disorders, infectious diseases, and neurodegenerative conditions, and amplification of the PIP5K1A locus on chromosome 1q has been reported in a subset of breast cancers^[4][5][6]. Compared with related type I isoforms, PIP5K1A belongs to a family that includes PIP5K1B and PIP5K1C, but individual isoforms display distinct cellular localization, regulatory interactions, and biological functions, supporting nonredundant contributions to PI(4,5)P₂ signaling networks^[4][7]. For experimental applications, pharmacological inhibition of PIP5K1A has emerged as a useful strategy to interrogate phosphoinositide-dependent signaling; the small-molecule inhibitor ISA-2011B suppresses PIP5Kα activity and impairs CD28-dependent calcium signaling, NF-AT activation, IL-2 expression, NF-κB activation, and pro-inflammatory cytokine transcription in human T lymphocytes^[8].