{Reference Type}: Journal Article {Title}: Phosphatidylinositol 3,4-bisphosphate: Out of the shadows and into the spotlight. {Author}: Ray J;Sapp DG;Fairn GD; {Journal}: Curr Opin Cell Biol {Volume}: 88 {Issue}: 0 {Year}: 2024 Jun 21 {Factor}: 8.386 {DOI}: 10.1016/j.ceb.2024.102372 {Abstract}: Phosphoinositide 3-kinases regulate many cellular functions, including migration, growth, proliferation, and cell survival. Early studies equated the inhibition of Class I PI3Ks with loss of; phosphatidylinositol 3,4,5-trisphosphate (PIP3), but over time, it was realised that these; treatments also depleted phosphatidylinositol 3,4-bisphosphate (PI(3,4)P2). In recent years, the; use of better tools and an improved understanding of its metabolism have allowed for the; identification of specific roles of PI(3,4)P2. This includes the production of PI(3,4)P2 and the; activation of its effector Akt2 in response to growth factor signalling. In contrast, a lysosomal pool of PI(3,4)P2 is a negative regulator of mTORC1 during growth factor deprivation. A growing body of literature also demonstrates that PI(3,4)P2 controls many dynamic plasmalemmal processes. The significance of PI(3,4)P2 in cell biology is increasingly evident.