The binding of different model membranes with PKCε C2 domain is not dependent on membrane curvature but affects the sequence of events during unfolding

Arch Biochem Biophys. 2021 Jul 15:705:108910. doi: 10.1016/j.abb.2021.108910. Epub 2021 May 12.

Abstract

The C2 domain of novel protein kinases C (nPKC) binds to membranes in a Ca2+-independent way contributing to the activation of these enzymes. We have studied the C2 domain of one of these nPKCs, namely PKCε, and confirmed that it establishes a strong interaction with POPA, which is clearly visible through changes in chemical shifts detected through 31P-MAS-NMR and the protection that it exerts on the domain against thermal denaturation seen through DSC and FT-IR. In this study, using two-dimensional correlation analysis (2D-COS) applied to infrared spectra, we determined the sequence of events that occur during the thermal unfolding of the domain and highlighted some differences when phosphatidic acid or cardiolipin are present. Finally, by means of FRET and DLS experiments, we wanted to determine the effect of membrane curvature on the domain/membrane interaction by using lysophosphatidylcholine to introduce positive curvature as a control and we observed that the effect of these phospholipids on the protein binding is not exerted through the change of membrane curvature.

Keywords: Infrared spectroscopy; Membrane curvature; Model membranes; Protein kinase Cε; Protein unfolding.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cardiolipins / metabolism
  • Cell Membrane / chemistry
  • Cell Membrane / metabolism*
  • Models, Molecular
  • Phosphatidic Acids / metabolism
  • Protein Binding
  • Protein Domains
  • Protein Kinase C-epsilon / chemistry*
  • Protein Kinase C-epsilon / metabolism*
  • Protein Unfolding*

Substances

  • Cardiolipins
  • Phosphatidic Acids
  • Protein Kinase C-epsilon