Transmembrane proteins are a type of protein that span across the cell membrane, with portions of the protein embedded in the lipid bilayer. These proteins play a crucial role in various cellular processes, such as cell signaling, transport of molecules across the membrane, and cell adhesion. Transmembrane proteins are commonly classified based on the number of times they pass through the membrane, with single-pass and multi-pass transmembrane proteins being the two main categories. Studying transmembrane proteins is important for understanding their functions and roles in health and disease, as they are targets for many pharmaceutical drugs and therapeutic interventions.