title: Membrane protein assembly patterns reflect selection for non-proliferative structures.
abstract: Membrane proteins that regulate solute movement are often built from multiple copies of an identical polypeptide chain. These complexes represent striking examples of self-assembling systems that recruit monomers only until a prescribed level for function is reached. Here we report that three modes of assembly - distinguished by sequence and stoichiometry - describe all helical membrane protein complexes currently solved to high resolution. Using the 13 presently available non-redundant homo-oligomeric structures, we show that two of these types segregate with protein function: one produces energy-dependent transporters, while the other builds channels for passive diffusion. Given such limited routes to functional complexes, membrane proteins that self-assemble exist on the edge of aggregation, susceptible to mutations that may underlie human diseases.
authors.affiliation: Division of Molecular Structure and Function, Research Institute, Hospital for Sick Children, 555 University Avenue, Toronto, Ont., Canada M5G 1X8.
authors.forename: Arianna
authors.initials: A
authors.lastname: Rath
authors.forename: Charles M
authors.initials: CM
authors.lastname: Deber
mesh_terms: D006801:Humans; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000502:physiology*; D011487:Protein Conformation
chemical_list: D026901:Membrane Transport Proteins