Functional Consequences of Membrane Protein Oligomerization

Oligomerization of H(+)-pyrophosphatase and its structural and functional consequences.

The H(+)-pyrophosphatase (H(+)-PPase) consists of a single polypeptide, containing 16 or 17 transmembrane domains. To determine the higher order oligomeric state of Streptomyces coelicolor H(+)-PPase, we constructed a series of cysteine substitution mutants and expressed them in Escherichia coli. Firstly, we analyzed the formation of disulfide bonds, promoted by copper, in mutants with single c...

Membrane protein folding and oligomerization: the two-stage model.

We discuss the view that the folding of many, perhaps most, integral membrane proteins can be considered as a two-stage process. In stage I, hydrophobic alpha-helices are established across the lipid bilayer. In stage II, they interact to form functional transmembrane structures. This model is suggested by the nature of transmembrane segments in known structures, refolding experiments, the asse...

Protein Oligomerization

Functional consequences of interactions between FAK and epithelial membrane protein 2 (EMP2).

PURPOSE Collagen gel contraction by ARPE-19 is controlled by epithelial membrane protein 2 (EMP2) through focal adhesion kinase (FAK) activation. The purpose of this study was to test the role of EMP2 in the cellular context of FAK activation. METHODS The ARPE-19 cell line was recombinantly modified to increase the expression of EMP2 and was used in this study. Quantification of FAK and Src p...

G protein-coupled receptor oligomerization revisited: functional and pharmacological perspectives.

Most evidence indicates that, as for family C G protein-coupled receptors (GPCRs), family A GPCRs form homo- and heteromers. Homodimers seem to be a predominant species, with potential dynamic formation of higher-order oligomers, particularly tetramers. Although monomeric GPCRs can activate G proteins, the pentameric structure constituted by one GPCR homodimer and one heterotrimeric G protein m...