A comprehensive comparison of transmembrane domains reveals organelle-specific properties.
The various membranes of eukaryotic cells differ in composition, but it is at present unclear if this results in differences in physical properties. The sequences of transmembrane domains (TMDs) of integral membrane proteins should reflect the physical properties of the bilayers in which they reside. We used large datasets from both fungi and vertebrates to perform a comprehensive comparison of the TMDs of proteins from different organelles. We find that TMDs are not generic but have organelle-specific properties with a dichotomy in TMD length between the early and late parts of the secretory pathway. In addition, TMDs from post-ER organelles show striking asymmetries in amino acid compositions across the bilayer that is linked to residue size and varies between organelles. The pervasive presence of organelle-specific features among the TMDs of a particular organelle has implications for TMD prediction, regulation of protein activity by location, and sorting of proteins and lipids in the secretory pathway.
Sharpe
Hayley J
HJ
MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.
Stevens
Tim J
TJ
Munro
Sean
S
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D015388:Organelles / Q000378:metabolism; D017434:Protein Structure, Tertiary; D040681:Structural Homology, Protein
D008565:Membrane Proteins