Preparation of monovalent follistatin-like 3-Fc-fusion protein and evaluation of its effects on muscle mass in mice

STAR Protoc. 2021 Sep 16;2(4):100839. doi: 10.1016/j.xpro.2021.100839. eCollection 2021 Dec 17.


Follistatin-like 3 (FSTL3) is an endogenous antagonist against transforming growth factor-β family ligands. Monovalent FSTL3-Fc fusion protein (mono-FSTL3-Fc) generated with knobs-into-holes technology overcomes limitations of current anti-myostatin therapies. We have developed a facile protocol for affinity purification of the Fc-fused protein from the supernatant of HEK293T cells stably expressing the protein. This protocol is advantageous by only requiring readily accessible equipment. We further outline the steps for validation of mono-FSTL3-Fc increasing systemic muscle mass in mice after intraperitoneal administration. For complete details on the use and execution of this protocol, please refer to Ozawa et al. (2021).

Keywords: Developmental biology; Health Sciences; Microscopy; Model Organisms; Protein expression and purification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Follistatin* / metabolism
  • Follistatin-Related Proteins* / genetics
  • HEK293 Cells
  • Humans
  • Mice
  • Muscles / metabolism
  • Transforming Growth Factor beta / metabolism


  • Follistatin
  • Follistatin-Related Proteins
  • Fstl3 protein, human
  • Fstl3 protein, mouse
  • Transforming Growth Factor beta