Sumoylation of p35 modulates p35/cyclin-dependent kinase (Cdk) 5 complex activity.
Cyclin-dependent kinase (Cdk) 5 is critical for central nervous system development and neuron-specific functions including neurite outgrowth as well as synaptic function and plasticity. Cdk5 activity requires association with one of the two regulatory subunits, called p35 and p39. p35 redistribution as well as misregulation of Cdk5 activity is followed by cell death in several models of neurodegeneration. Posttranslational protein modification by small ubiquitin-related modifier (SUMO) proteins (sumoylation) has emerged as key regulator of protein targeting and protein/protein interaction. Under cell-free in vitro conditions, we found p35 covalently modified by SUMO1. Using both biochemical and FRET-/FLIM-based approaches, we demonstrated that SUMO2 is robustly conjugated to p35 in cells and identified the two major SUMO acceptor lysines in p35, K246 and K290. Furthermore, different degrees of oxidative stress resulted in differential p35 sumoylation, linking oxidative stress that is encountered in neurodegenerative diseases to the altered activity of Cdk5. Functionally, sumoylation of p35 increased the activity of the p35/Cdk5 complex. We thus identified a novel neuronal SUMO target and show that sumoylation is a likely candidate mechanism for the rapid modulation of p35/Cdk5 activity in physiological situations as well as in disease.
Department of Neurology, University Medical Center Göttingen, Waldweg 33, 37073, Göttingen, Germany.
Anja
A
Büchner
Petranka
P
Krumova
Sundar
S
Ganesan
Mathias
M
Bähr
Katrin
K
Eckermann
Jochen H
JH
Weishaupt
D000818:Animals; D002461:Cell Line, Transformed; D002474:Cell-Free System; D017124:Conserved Sequence; D051360:Cyclin-Dependent Kinase 5 / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008239:Lysine / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D018384:Oxidative Stress; D011485:Protein Binding; D025941:Protein Interaction Mapping; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D025842:SUMO-1 Protein / Q000378:metabolism*; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism*; D058207:Sumoylation / Q000502:physiology
D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; D025842:SUMO-1 Protein; C495501:SUMO1 protein, human; C117909:SUMO2 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins; C089495:neuronal Cdk5 activator (p25-p35); D051360:Cyclin-Dependent Kinase 5; D008239:Lysine