We elucidated the specific roles of class II PI3K isoforms in various contexts. For instance, our research indicates that PI3K-C2α is not only crucial for mouse embryo development but also plays a vital role in clathrindependent endocytosis and vesicle trafficking. We observed that the disruption of PI3K-C2α results in impaired embryonic development and disturbed intracellular transport, underscoring its significance in these processes. Additionally, our investigations have uncovered that PI3K-C2α is implicated in the activation of Rab11, a small GTPase that governs intracellular transport and recycling. These findings provide insights into the regulatory mechanisms mediated by PI3K-C2α in membrane trafficking. Furthermore, our investigations have revealed the significance of PI3K-C2α in the control of cell division, particularly in the context of breast cancer tumorigenesis. We have observed that altered expression or activity of PI3K-C2α impacts cell proliferation and division, suggesting its involvement in the regulation of these processes in cancer cells. Similarly, our studies have concentrated on the role of PI3K-C2β in mitosis progression, specifically in prostate cancer. Through our research, we have clarified the importance of PI3K-C2β in modulating mitotic events and ensuring proper cell division in prostate cancer cells. These findings shed light on the specific functions of PI3K-C2β in the context of cancer biology and provide a potential target for therapeutic interventions. More recently, our investigations have revealed an unexpected role of PI3K-C2β-mediated lipid signaling in the regulation of mTORC1-dependent neuronal excitability. We discovered that PI3K-C2β activity influences neuronal excitability in both mice and humans through its impact on mTORC1 signaling. This discovery highlights the involvement of class II PI3Ks in neuronal function and unveils a novel link between lipid signaling and neuronal excitability. Additionally, our research has clarified the subcellular localization of PI3K-C2γ on early endosomes, offering insights into its compartmentalization within the cell.