Background:

Previously thought to be simple membrane anchors, the transmembrane domains (TMDs) of single-pass membrane proteins are now known to have a number of functions, including protein localization in the cell and the transfer of signals across the membrane. Single amino acid polymorphisms in TMDs in can greatly affect protein function, leading to disease phenotypes and greatly altering aspects such as TMD-TMD dimerization. At the moment, the relative importance of TMD regions for the cell is not fully clear. Are nearly all TMDs participating in TMD-TMD interactions? Are a proportion of TMDs really just membrane anchors?

The concept:

In a protein sequence, the most functionally important amino acids tend to be highly conserved among homologous proteins. Multiple sequence alignments against homologs therefore allow the identification of key residues in protein families, such as the active sites of enzymes or the interface residues between obligate dimers. Ongoing projects use bioinformatic tools to examine the conservation of amino acids in transmembrane helices. The aim is to better understand the evolution of TMDs, predict key residues in TMD function, and develop simple but powerful tools for TMD sequence analysis.