Skip to main content
. Author manuscript; available in PMC: 2012 Dec 14.
Published in final edited form as: Nature. 2012 Jan 11;481(7382):463–468. doi: 10.1038/nature10777

Figure 4. Fndc5 is proteolytically cleaved and secreted from cells.

Figure 4

a, Schematic representation of the Fndc5 protein structure (top), flag-tagged Fndc5 protein (middle) and irisin (bottom). SP = signal peptide, H = hydrophobic domain, C = c-terminal domain, Flag = FLAG epiotope. b, 293 cells transfected with a vector expressing the c-terminal flag tagged Fndc5 (CTF-F5, third panel from a), followed by isolation of cell and culture media protein. Samples were adjusted for protein content and western blots were performed against the FLAG antigen (left) or Fndc5 (right). This was repeated in several experiments with similar results. Adjusting for volume (instead of protein content) also gave similar results. C = cell fraction and M = media fraction. c, 293 cells transfected with a vector expressing Fndc5-CTF, followed by isolation of cell and media protein. Respective protein fraction was then treated with PNGase F followed by western blot against Fndc5 after SDS-PAGE. d, representation of the full-length Fndc5 and the irisin fragment mapped by mass spectrometry (bold and underlined).