Regulation of PI3K signalling by the phosphatidylinositol transfer protein PITP-alpha during axonal extension in hippocampal neurons

Authors:
Cosker KE, Shadan S, van Diepen M, Morgan C, Li M, Allen-Baume V, Hobbs C, Doherty P, Cockcroft S, Eickholt BJ
In:
Source: J Cell Sci
Publication Date: (2008)
Issue: 121(Pt 6): 796-803
Research Area:
Neurobiology
Cells used in publication:
Neuron, hippo/cortical, rat
Species: rat
Tissue Origin: brain
Platform:
Nucleofector® I/II/2b
Abstract
Phosphatidylinositol transfer proteins (PITPs) mediate the transfer of phosphatidylinositol (PtdIns) or phosphatidylcholine (PtdCho) between two membrane compartments, thereby regulating the interface between signalling, phosphoinositide (PI) metabolism and membrane traffic. Here, we show that PITPalpha is enriched in specific areas of the postnatal and adult brain, including the hippocampus and cerebellum. Overexpression of PITPalpha, but not PITPbeta or a PITPalpha mutant deficient in binding PtdIns, enhances laminin-dependent extension of axonal processes in hippocampal neurons, whereas knockdown of PITPalpha protein by siRNA suppresses laminin and BDNF-induced axonal growth. PITPalpha-mediated axonal outgrowth is sensitive to phosphoinositide 3-kinase (PI3K) inhibition and shows dependency on the Akt/GSK-3/CRMP-2 pathway. We conclude that PITPalpha controls the polarized extension of axonal processes through the provision of PtdIns for localized PI3K-dependent signalling.