Phosphatidylinositol 3-phosphate (PI3P) is a type of phospholipid found in cell membranes, particularly in the endosomal system. It plays a crucial role in cellular processes such as membrane trafficking, cell signaling, and the regulation of various cellular functions. PI3P is produced by the enzyme phosphoinositide 3-kinase (PI3K) and is involved in the recruitment of proteins that contain specific binding domains. In addition to its role in membrane dynamics, PI3P is important for the regulation of autophagy, a process that helps cells recycle components and maintain homeostasis. Abnormal levels of PI3P can be associated with various diseases, including cancer and neurodegenerative disorders, highlighting its significance in health and disease.