Phosphoinositide 3-kinase (PI3K) is an enzyme that plays a crucial role in cellular signaling pathways. It is involved in various cellular processes, including growth, proliferation, and survival. PI3K works by phosphorylating phosphoinositides, which are lipids found in cell membranes, leading to the activation of downstream signaling proteins. There are several classes of PI3K, each with distinct functions and regulatory mechanisms. The most studied class, Class I PI3K, is activated by receptor tyrosine kinases and is important in cancer research due to its role in tumor growth and metabolism. Understanding PI3K's function can help develop targeted therapies for various diseases.