PIPKH, also known as PIP5KL1 (phosphatidylinositol-4-phosphate 5-kinase-like 1), is a 394 amino acid phosphoinositide kinase-like protein that contains one PIPK domain. Although PIPKH lacks intrinsic lipid kinase activity, it associates with type I PIPKs and may play a role in localization of PIPK activity. Encoded by a gene that maps to human chromosome 9q34.11, PIPKH localizes to cytoplasm, specifically to large cytoplasmic vesicular structures, and exists as two alternatively spliced isoforms. Highly expressed in brain and testis, PIPKH is also expressed at very low levels in heart, spleen, lung, liver, skeletal muscle and kidney. PIPKH heterodimerizes with other type I phosphatidylinositol-4-phosphate 5-kinases, and may function as a scaffold to localize and regulate kinases to specific cell compartments. Overexpression of PIPKH may suppress cell proliferation and migration in human gastric cancer cells and may also inhibit cervical cancer formation.