New insights into the molecular mechanisms specifying neuronal polarity in vivo.
The polarization of axon and dendrites underlies the ability of neurons to integrate and transmit information in the brain. Important progress has been made toward the identification of the molecular mechanisms regulating neuronal polarization using primarily in vitro approaches such as dissociated culture of rodent hippocampal neurons. The predominant view emerging from this paradigm is that neuronal polarization is initiated by intrinsic activation of signaling pathways underlying the initial break in neuronal symmetry that precedes the future asymmetric growth of the axon. Recent evidence shows that (i) axon-dendrite polarization is specified when neurons engage migration in vivo, (ii) that a kinase pathway defined by LKB1and SAD-kinases (Par4/Par1 dyad) is required for proper neuronal polarization in vivo and that (iii) extracellular cues can play an instructive role during neuronal polarization. Here, we review some of these recent results and highlight future challenges in the field including the determination of how extracellular cues control intracellular responses underlying neuronal polarization in vivo.
Neuroscience Center, Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599-7250, USA.
Anthony P
AP
Barnes
David
D
Solecki
Franck
F
Polleux
D000818:Animals; D001921:Brain / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics*; D019070:Cell Lineage / Q000235:genetics; D016764:Cell Polarity / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D006801:Humans; D016501:Neurites / Q000378:metabolism / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*
D011494:Protein Kinases