The Intrinsically Unfolded Proteins Fra-1 and c-Fos induce membrane remodelling in DMPC and DMPC:PIP2 vesicles

CECILIA GAGGIOTTI; BORIOLI, GRACIELA

Salta

Congreso; XXXIV SAB Meeting, WorkshopCeBEM, 3rd Latin American Protein Society Meeting; 2010

The transcription factors Fra-1 and cFos are amphitropic, flexible (1) and belong to the b-ZIP family, having a leucine zipper and a basic domain (BD) that interact with DNA uppon dimerization (2). The myristoylated alanine-rich C kinase substrate, MARCKS, binds to the membrane by hydrophobic insertion and electrostatic interaction that is accomplished by the polybasic region of the effector domain (ED) (3). Fra‑1, c-Fos and MARCKS are Intrinsically Unfolded Proteins (IUPs) excepting in the regions corresponding to the LZ-BD and ED as predicted by the program Disopred 2 (4). We explored the proteins three-dimensional activities and possible bilayer remodeling effects (Fig. 1) that were anticipated by X ray small angle studies of proteoliposomes in solution. To this purpose, the effects of Fra-1, c-Fos and MARCKS on DMPC and DPMC:PIP2 (1900:100) vesicles, were assessed with Flourescence Resonance Energy Transfer (FRET) assays, using NDB-DPPE and Rho-DPPE lipid probes, in varying pH and ionic strength buffers.