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Interplay between MPIase, YidC, and PMF during Sec-independent insertion of membrane proteins

Yuta Endo1, Yuko Shimizu2, Hanako Nishikawa2

  • 1The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Japan.

Life Science Alliance
|October 13, 2021
PubMed

Insights

Membrane protein insertion depends on factors like YidC and proton motive force (PMF). This study reveals that N-terminal charges and synthesis levels determine these dependencies, highlighting the interplay between MPIase, YidC, and PMF.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Membrane Biology

Background:

  • Integral membrane proteins with N-out topology insert into membranes via YidC and proton motive force (PMF)-dependent mechanisms.
  • The molecular basis for varying dependencies on these insertion factors remains incompletely understood.

Purpose of the Study:

  • To investigate the in vitro mechanisms determining insertion factor dependency for model proteins Pf3-Lep and its V15D mutant.
  • To elucidate the roles of glycolipid MPIase, YidC, and PMF in protein insertion.

Main Methods:

  • In vitro reconstitution of liposomes with MPIase, YidC, and F0F1-ATPase.
  • Analysis of protein insertion dependency on MPIase, YidC, and PMF using model proteins Pf3-Lep and V15D mutant.
  • Depletion and dissipation experiments to assess factor requirements.

Main Results:

  • Glycolipid MPIase is essential for the insertion of both Pf3-Lep and V15D.
  • YidC and PMF stimulate Pf3-Lep insertion, with dependency increasing with synthesis level.
  • V15D insertion is stimulated by both YidC and PMF, independent of synthesis level.

Conclusions:

  • N-terminal charges and protein synthesis levels are key determinants of YidC and PMF dependencies.
  • An interplay exists between MPIase, YidC, and PMF in regulating membrane protein insertion.
  • These findings provide insights into the molecular basis of membrane protein biogenesis.

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