This article, Fibrosporine, was written by RelentlessRecusant. Please do not edit this fiction without the writer's permission.

Fibrosporine ("EP 613593") is a specific small-molecule agonist of TGFβRI (ALK5) that is naturally found in imulsion extract and is believed to in part mediate imulsion's mutagenic properties to the adult human. It was originally characterized by Ellis Pharmaceuticals in their studies of imulsion extract and in the Ellis Pharmaceutical internal collection, is referenced as "EP 613593".

Canonical TGFβ signaling through TGFβRI has been broadly implicated in a diverse number of biological activities, such as fibrosis[1], cancer[2], the epithelial-to-mesenchymal transition[2], and immunological surveillance[2]. Fibrosporine induces global collagen deposition and excessive fibrosity in the adult human, in accordance with the role of TGFβ signaling in extracellular matrix generation.[1] Fibrosporine serves as a mimetic of the TGFβ-1, TGFβ-2, and TGFβ-3 isoforms of ligands through artificial constitutive stimulation of TGFβRI.


  1. 1.0 1.1 Ishida et. al (2006). Intracellular TGF-β Receptor Blockade Abrogates Smad-Dependent Fibroblast Activation In Vitro and In Vivo. Journal of Investigative Dermatology (126): 1733-1744.
  2. 2.0 2.1 2.2 Yingling et. al (2004). Development of TGF-β Signalling Inhibitors for Cancer Therapy. Nature Reviews Drug Discovery (3): 1011-1022.

Behind the ScenesEdit

  • While Fibrosporine is a fictitious activator of TGFβRI, the biological activities of the TGFβ ligands and TGFβRI described are indeed real-world.