TY - JOUR
T1 - Stable membrane orientations of small dual-topology membrane proteins
AU - Fluman, Nir
AU - Tobiasson, Victor
AU - von Heijne, Gunnar
N1 - We thank Harry L. T. Mobley (University of Michigan Medical School) for providing genomic DNA of Proteus mirabilis, Guenter Kramer (Centre for Molecular Biology, Heidelberg) for advice in operon construct design, Jan-Willem DeGier (Stockholm University) for providing several reagents, and members of our group for helpful discussions. This work was supported by grants from the Knut and Alice Wallenberg Foundation, the Swedish Research Council, and the Swedish Cancer Foundation (to G.v.H.). N.F. was supported by long-term postdoctoral fellowships from EMBO/Marie Curie Actions (ALTF 211-2014) and from the Human Frontiers Science Program (LT000277/2015-L). Author contributions: N.F. and G.v.H. designed research; N.F. and V.T. performed research; N.F., V.T., and G.v.H. analyzed data; and N.F. and G.v.H. wrote the paper.
PY - 2017/7/25
Y1 - 2017/7/25
N2 - The topologies of alpha-helical membrane proteins are generally thought to be determined during their cotranslational insertion into the membrane. It is typically assumed that membrane topologies remain static after this process has ended. Recent findings, however, question this static view by suggesting that some parts of, or even the whole protein, can reorient in the membrane on a biologically relevant time scale. Here, we focus on antiparallel homo- or heterodimeric small multidrug resistance proteins and examine whether the individual monomers can undergo reversible topological inversion (flip flop) in the membrane until they are trapped in a fixed orientation by dimerization. By perturbing dimerization using various means, we show that the membrane orientation of a monomer is unaffected by the presence or absence of its dimerization partner. Thus, membrane-inserted monomers attain their final orientations independently of dimerization, suggesting that wholesale topological inversion is an unlikely event in vivo.
AB - The topologies of alpha-helical membrane proteins are generally thought to be determined during their cotranslational insertion into the membrane. It is typically assumed that membrane topologies remain static after this process has ended. Recent findings, however, question this static view by suggesting that some parts of, or even the whole protein, can reorient in the membrane on a biologically relevant time scale. Here, we focus on antiparallel homo- or heterodimeric small multidrug resistance proteins and examine whether the individual monomers can undergo reversible topological inversion (flip flop) in the membrane until they are trapped in a fixed orientation by dimerization. By perturbing dimerization using various means, we show that the membrane orientation of a monomer is unaffected by the presence or absence of its dimerization partner. Thus, membrane-inserted monomers attain their final orientations independently of dimerization, suggesting that wholesale topological inversion is an unlikely event in vivo.
UR - http://www.scopus.com/inward/record.url?scp=85025806467&partnerID=8YFLogxK
U2 - https://doi.org/10.1073/pnas.1706905114
DO - https://doi.org/10.1073/pnas.1706905114
M3 - مقالة
SN - 0027-8424
VL - 114
SP - 7987
EP - 7992
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 30
ER -