Acts as a lipid transfer protein. Preferentially captures and shuttles two lipid second messengers, i.e., phosphatidylinositol 4,5- bisphosphate and phosphatidylinositol 3,4,5-trisphosphate and increases their levels in the plasma membrane. Additionally, may also function as a lipid-presenting protein to enhance the activity of the PI3K-AKT and MEK-ERK pathways. May act as a regulator of tumorigenesis through its activation of phospholipid signaling. On PDGF activation, translocates from cytoplasm to plasma membrane. Widely expressed (at protein level). The N-terminal domain (AA 2-20) is essential for its effect on cell growth and survival. Deficient mice develop normally during the first 3 months of life under pathogen-free conditions. However, following subcutaneous injection of the carcinogen 3-methylcholanthrene, deficient mice exhibit markedly delayed skin tumor onset and reduced tumor size compared with wild-type mice. Belongs to the TNFAIP8 family.