Identification of new kinase clusters required for neurite outgrowth and retraction by a loss-of-function RNA interference screen

• Published in: Cell death and differentiation Vol. 15; no. 2; pp. 283 - 298
• Main Authors: Loh, S H Y, Francescut, L, Lingor, P, Bähr, M, Nicotera, P
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-02-2008; Nature Publishing Group
• Subjects: Alzheimer's disease; Animals; Apoptosis; Biochemistry; Biomedical and Life Sciences; Cell Biology; Cell Cycle Analysis; Cell death; Disease; Drosophila; Growth Cones - physiology; Humans; Insects; Kinases; Life Sciences; Mitochondrial DNA; Nervous system; Neurites - metabolism; Neurites - physiology; Neurodegeneration; original-paper; Parkinson's disease; Phosphorylation; Protein Kinases - metabolism; Proteins; Rats; Rats, Wistar; Retinitis Pigmentosa - genetics; Retinitis Pigmentosa - metabolism; RNA Interference; Signal transduction; Stem Cells; Toxicology; United Kingdom > UK; Germany; neurite retraction; RNAi screen; neurite outgrowth; human kinases
• ISSN: 1350-9047; 1476-5403
• DOI: 10.1038/sj.cdd.4402258

Disruption of synaptic integrity, loss of connectivity and axodendritic degeneration are early and essential components of neurodegeneration. Although neuronal cell death mechanisms have been thoroughly investigated, less is known about the signals involved in axodendritic damage and the processes involved in regeneration. Here we conducted a genome-wide RNA interference-based forward genetic screen, using small interfering RNA targeting all human kinases, and identified clusters of kinases families essential for growth cone collapse, neurite retraction and neurite outgrowth. Of 59 kinases identified as positive regulators of neurite outgrowth, almost 50% were in the tyrosine kinase/tyrosine kinase-like (TK/TKL) receptor subgroups, underlining the importance of extracellular ligands in this process. Neurite outgrowth was inhibited by 66 other kinases, none of which were TK/TKL members, whereas 79 kinases inhibited lysophosphatidic acid-induced neurite retraction. Twenty kinases were involved in both inhibitory processes suggesting shared mechanisms. Within this group of 20 kinases, some (ULK1, PDK1, MAP4K4) have been implicated previously in axonal events, but others (MAST2, FASTK, CKM and DGUOK) have not. For a subset of kinases, the effect on neurite outgrowth was validated in rat primary cerebellar cultures. The ability to affect regeneration was further tested in a model of axodendritic lesion using primary rat midbrain cultures. Finally, we demonstrated that haploinsufficiency of two members of the AGC kinase subgroup, ROCK1 and PKN1, was able to suppress retinal degeneration in
Drosophila
model of class III Autosomal Dominant Retinitis Pigmentosa.