What are the functions of transmembrane proteins?

Transmembrane proteins are a specialized type of membrane protein that traverse the entire lipid bilayer of the cell membrane with regions that span the hydrophobic core of the membrane as well as the aqueous environment on the other side. 

Transmembrane proteins serve 3 critical functions that help in various cellular processes. 

1. Transport of ions and molecules: The primary function of transmembrane proteins is to serve as channels or gates that facilitate the entry and exit of molecules and across the cell membranes. This is crucial for regulating various metabolic processes in organisms. 
2. Cell signaling: G protein-coupled receptors are a type of specialized transmembrane proteins that act as receptors which bind to specific signaling molecules, transmitting signals from the extracellular environment to the inside of the cell. This is essential for processes such as cell communication and response to external stimuli.
3. Structural Support: Transmembrane proteins contribute to the structural integrity of the cell membrane by anchoring to the lipid bilayer, which helps to maintain the shape and stability of the cell.