The "PX domain" refers to a specific protein domain found in various proteins across different organisms. It is characterized by its role in binding to phosphoinositides, which are important lipids involved in cellular signaling and membrane dynamics. The PX domain is often associated with proteins that play a role in endocytosis and vesicle trafficking. Proteins containing the PX domain are crucial for cellular processes, including the regulation of cell membrane composition and signal transduction. Understanding the PX domain helps researchers explore its functions in health and disease, particularly in areas like cancer and neurodegenerative disorders.