Substrate recognition component of a SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Probably recognizes and binds to phosphorylated target proteins (By similarity). Recognizes FZO1 and regulates the amount of FZO1. Regulatory factor for the mitochondrial fusion machinery. Required for mitochondrial DNA maintenance. Protein modification; protein ubiquitination. Interacts with SKP1. Component of the probable SCF(MDM30) complex containing CDC53, SKP1, RBX1 and MDM30. Interacts with SKP1 and FZO1.