A nestin scaffold links Cdk5/p35 signaling to oxidant-induced cell death.
The intermediate filament protein, nestin, has been implicated as an organizer of survival-determining signaling molecules. When nestin expression was related to the sensitivity of neural progenitor cells to oxidant-induced apoptosis, nestin displayed a distinct cytoprotective effect. Oxidative stress in neuronal precursor cells led to downregulation of nestin with subsequent activation of cyclin-dependent kinase 5 (Cdk5), a crucial kinase in the nervous system. Nestin downregulation was a prerequisite for the Cdk5-dependent apoptosis, as overexpression of nestin efficiently inhibited induction of apoptosis, whereas depletion of nestin by RNA interference had a sensitizing effect. When the underlying link between nestin and Cdk5 was analyzed, we observed that nestin serves as a scaffold for Cdk5, with binding restricted to a specific region following the alpha-helical domain of nestin, and that the presence and organization of nestin regulated the sequestration and activity of Cdk5, as well as the ubiquitylation and turnover of its regulator, p35. Our data imply that nestin is a survival determinant whose action is based upon a novel mode of Cdk5 regulation, affecting the targeting, activity, and turnover of the Cdk5/p35 signaling complex.
Sahlgren
Cecilia M
CM
Turku Centre for Biotechnology, University of Turku and Abo Akademi University, Turku, Finlandand.
Pallari
Hanna-Mari
HM
He
Tao
T
Chou
Ying-Hao
YH
Goldman
Robert D
RD
Eriksson
John E
JE
D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D002460:Cell Line; D051360:Cyclin-Dependent Kinase 5 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D064231:Nestin; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects / Q000235:genetics; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary / Q000235:genetics; D034622:RNA Interference / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism
D007381:Intermediate Filament Proteins; D046912:Multiprotein Complexes; C577484:NES protein, human; D009419:Nerve Tissue Proteins; D064231:Nestin; D016877:Oxidants; D025801:Ubiquitin; C089495:neuronal Cdk5 activator (p25-p35); D006861:Hydrogen Peroxide; D051360:Cyclin-Dependent Kinase 5