A protein molecule (or assembly of proteins) that is permanently attached or firmly anchored in the plasma membrane via its hydrophobic domains interacting with the membrane phospholipids.
Integral membrane proteins may be classified into two major groups: (1) transmembrane proteins, and (2) integral monotropic proteins.
The more common type is the transmembrane protein that spans the entire plasma membrane.
IMPs include transporters, channels, receptors, enzymes, structural membrane-anchoring domains, proteins involved in accumulation and transduction of energy, and proteins responsible for cell adhesion. Examples of which are integrin, cadherin, insulin receptor, NCAM, selectin, glycophorin, rhodopsin, etc.
Synonym: intrinsic protein.
Compare:peripheral membrane protein.
See also: membrane protein, cell membrane, fluid mosaic model.