title: CDKL5 and Shootin1 Interact and Concur in Regulating Neuronal Polarization.
abstract: In the last years, the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene has been associated with epileptic encephalopathies characterized by the early onset of intractable epilepsy, severe developmental delay, autistic features, and often the development of Rett syndrome-like features. Still, the role of CDKL5 in neuronal functions is not fully understood. By way of a yeast two hybrid screening we identified the interaction of CDKL5 with shootin1, a brain specific protein acting as a determinant of axon formation during neuronal polarization. We found evidence that CDKL5 is involved, at least in part, in regulating neuronal polarization through its interaction with shootin1. Indeed, the two proteins interact in vivo and both are localized in the distal tip of outgrowing axons. By using primary hippocampal neurons as model system we find that adequate CDKL5 levels are required for axon specification. In fact, a significant number of neurons overexpressing CDKL5 is characterized by supernumerary axons, while the silencing of CDKL5 disrupts neuronal polarization. Interestingly, shootin1 phosphorylation is reduced in neurons silenced for CDKL5 suggesting that the kinase affects, directly or indirectly, the post-translational modification of shootin1. Finally, we find that the capacity of CDKL5 to generate surplus axons is attenuated in neurons with reduced shootin1 levels, in agreement with the notion that two proteins act in a common pathway. Altogether, these results point to a role of CDKL5 in the early steps of neuronal differentiation that can be explained, at least in part, by its association with shootin1.
authors: Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Biotechnology and Life Sciences, Centre of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy.
authors: Mohammad Sarfaraz
authors: MS
authors: Nawaz
authors: Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Biotechnology and Life Sciences, Centre of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy.
authors: Elisa
authors: E
authors: Giarda
authors: San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Insitute, 20132 Milan, Italy.
authors: Francesco
authors: F
authors: Bedogni
authors: Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Biotechnology and Life Sciences, Centre of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy.
authors: Paolo
authors: P
authors: La Montanara
authors: Molecular Histology and Cell Growth Unit, Fondazione Istituto Nazionale Genetica Molecolare (INGM), 20122 Milan, Italy.
authors: Sara
authors: S
authors: Ricciardi
authors: Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Biotechnology and Life Sciences, Centre of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy.
authors: Dalila
authors: D
authors: Ciceri
authors: Laboratory of Biochemistry and Functional Proteomics, Department of Science and High Technology, Centre of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy.
authors: Tiziana
authors: T
authors: Alberio
authors: San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Insitute, 20132 Milan, Italy.|Department of Medical Biotechnology and Translational Medicin, University of Milan, 20090 Segrate, Italy.
authors: Nicoletta
authors: N
authors: Landsberger
authors: Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Biotechnology and Life Sciences, Centre of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy.
authors: Laura
authors: L
authors: Rusconi
authors: Laboratory of Genetic and Epigenetic Control of Gene Expression, Department of Biotechnology and Life Sciences, Centre of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy.
authors: Charlotte
authors: C
authors: Kilstrup-Nielsen
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism*; D016764:Cell Polarity / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D009419:Nerve Tissue Proteins; D017346:Protein Serine-Threonine Kinases; C533690:CDKL5 protein, mouse