TY - JOUR
T1 - Single-Molecule Analyses Reveal Rhomboid Proteins Are Strict and Functional Monomers in the Membrane
AU - Kreutzberger, Alex J.B.
AU - Urban, Siniša
N1 - Funding Information:
This work was funded, in part, by an Innovator Award from the Discovery Fund of Johns Hopkins University (to S.U.), and award 2007-31766 from the David and Lucille Packard Foundation (to S.U.).
Publisher Copyright:
© 2018 Biophysical Society
PY - 2018/11/6
Y1 - 2018/11/6
N2 - Intramembrane proteases hydrolyze peptide bonds within the membrane as a regulatory paradigm that is conserved across all forms of cellular life. Many of these enzymes are thought to be oligomeric, and that their resulting quaternary interactions form the basis of their regulation. However, technical limitations have precluded directly determining the oligomeric state of intramembrane proteases in any membrane. Using single-molecule photobleaching, we determined the quaternary structure of 10 different rhomboid proteins (the largest superfamily of intramembrane proteases) and six unrelated control proteins in parallel detergent micelle, planar supported lipid bilayer, and whole-cell systems. Bacterial, parasitic, insect, and human rhomboid proteases and inactive rhomboid pseudoproteases all proved to be monomeric in all membrane conditions but dimeric in detergent micelles. These analyses establish that rhomboid proteins are, as a strict family rule, structurally and functionally monomeric by nature and that rhomboid dimers are unphysiological.
AB - Intramembrane proteases hydrolyze peptide bonds within the membrane as a regulatory paradigm that is conserved across all forms of cellular life. Many of these enzymes are thought to be oligomeric, and that their resulting quaternary interactions form the basis of their regulation. However, technical limitations have precluded directly determining the oligomeric state of intramembrane proteases in any membrane. Using single-molecule photobleaching, we determined the quaternary structure of 10 different rhomboid proteins (the largest superfamily of intramembrane proteases) and six unrelated control proteins in parallel detergent micelle, planar supported lipid bilayer, and whole-cell systems. Bacterial, parasitic, insect, and human rhomboid proteases and inactive rhomboid pseudoproteases all proved to be monomeric in all membrane conditions but dimeric in detergent micelles. These analyses establish that rhomboid proteins are, as a strict family rule, structurally and functionally monomeric by nature and that rhomboid dimers are unphysiological.
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U2 - 10.1016/j.bpj.2018.09.024
DO - 10.1016/j.bpj.2018.09.024
M3 - Article
C2 - 30342748
AN - SCOPUS:85054821872
SN - 0006-3495
VL - 115
SP - 1755
EP - 1761
JO - Biophysical journal
JF - Biophysical journal
IS - 9
ER -