Phospholipid (cell surface)

Cell surface phospholipids" refers to the class of **phospholipids** located in the outer leaflet of the plasma membrane bilayer[1][3][4][5][7]. Phospholipids are *amphipathic* molecules composed of a hydrophilic (polar) phosphate-containing head and two hydrophobic fatty acid tails. In aqueous environments, they spontaneously organize into bilayers with hydrophilic heads interfacing with water and hydrophobic tails shielded inward, forming the basic structure of all biological membranes including the cell surface[5][7]. This bilayer creates a **selective barrier**, regulating the movement of substances into and out of the cell and contributing to cell signaling, membrane fluidity, and compartmentalization of cellular functions[1][2][3][4][5][6]. Distinct types of phospholipids (e.g., phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, phosphatidylinositol) exist, each with specific functions and distributions within the membrane[6]. However, "cell surface phospholipid" is a *structural class*, not a discrete molecular target or receptor, and does not function as a canonical drug target like a receptor, ion channel, or enzyme[1][4][5]. Targeting phospholipids directly is therapeutically impractical due to their ubiquity and essential roles in all cell types. Notes: - The entry is **incorrect as a therapeutic target**: "Cell surface phospholipids" represent a general class of molecules and do not constitute a specific, actionable molecular target for drugs or biologics[1][4][5]. There are no drugs that specifically target cell surface phospholipids as a class; rather, drugs may act on proteins or enzymes interacting with them. This term is not standard for molecular target annotation.

Other names

Cell surface phospholipidMembrane phospholipidPlasma membrane phospholipid