INPP5K (inositol polyphosphate-5-phosphatase K) is a lipid phosphatase that hydrolyzes the 5-phosphate group from phosphoinositides, including PtdIns(4,5)P2 and PtdIns(3,4,5)P3 1. The protein contains an N-terminal catalytic domain and a C-terminal SKICH domain responsible for protein-protein interactions and subcellular localization, with predominant concentration in the endoplasmic reticulum 1. INPP5K regulates multiple cellular processes including insulin signaling, cytoskeletal organization, and membrane dynamics. It controls the structural conformation of receptors like IL-7R by modulating PtdIns(4,5)P2 levels, which affects receptor signaling and cellular differentiation 2. In neurons, INPP5K maintains the nonuniform distribution of ER-plasma membrane contacts, working upstream of Atlastin-1 to balance ER tubules and sheets 3. Biallelic mutations in INPP5K cause a rare autosomal recessive disorder characterized by congenital muscular dystrophy, cataracts, short stature, and intellectual disability 4. This condition shares molecular pathways with Marinesco-Sjögren syndrome through dysregulation of PHGDH, suggesting potential therapeutic targets 4. INPP5K also functions as a tumor suppressor, with reduced expression associated with poor prognosis in liver cancer 56.