SCFFbxw5 targets kinesin-13 proteins to facilitate ciliogenesis

Using substrate screening on protein microarrays we identified the kinesin-13 Kif2c/MCAK as a novel target of the ubiquitin E3 ligase SCF-Fbxw5. In cells, SCF-Fbxw5 ubiquitylates MCAK for proteasomal degradation during G2/M thereby facilitating ciliogenesis in the following G0 phase. Here, we performed mass spectrometry analysis to identify lysine residues of recombinant MCAK that are specifically ubiquitylated in vitro by SCF-Fbxw5 in concert with the E2 enzyme Cdc34 based on diGly remnants after trypsin digestion.