Fig. 2
From: The role of the ubiquitin proteasome system in cerebellar development and medulloblastoma
The SCF ligases, Fbw7, SKP2, and β-TrCP regulate oncogenes and tumor suppressors in medulloblastomas: Schematic illustration of the cell summarizes the important SCF ligases, Fbw7, SKP2, and β-TrCP and important substrate that after ubiquitination targeted by proteasom for degradation. Fbw7 - ubiquitin ligase F-box WD repeat containing protein 7; Skp2 - ubiquitin ligase S-phase kinase associated protein; Β-TrCP - ubiquitin ligase B-transducin repeats-containing protein. 
Ubiquitin, Sub; substrate, tf; transcription factor