Protein kinase C mediates neurite guidance at an astrocyte boundary.
During development, astrocytes play an active role in directing axons to their final targets. This guidance has been attributed in part to the increased expression of guidance molecules, such as tenascin-C and chondroitin sulfate proteoglycans, by boundary-forming astrocytes. We have previously used a culture model of astrocyte boundaries to demonstrate that neurites growing on permissive astrocytes alter their trajectory as they encounter less-permissive astrocytes. The present study investigated the role of the protein kinase C (PKC) family of signal transduction molecules in this form of axonal guidance. Neurons were plated onto mixed astrocyte monolayers in the presence of agents that either downregulate the phorbol ester-sensitive PKC isoforms or inhibit PKC. Both downregulation and inhibition of PKC increased the percentage of neurons that crossed onto the nonpermissive astrocytes. On astrocyte monolayers, phorbol ester modulation of PKC but not PKC inhibitors resulted in a decrease in overall neurite extension. PKC inhibitors also caused a similar alteration in the neuronal response to cell-free boundaries, at concentrations that did not inhibit neurite extension. Thus, phorbol-ester-sensitive PKC isoforms direct the guidance of neurites by astrocyte-derived matrix molecules.
Powell
E M
EM
Department of Pharmacology, UMDNJ-Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA.
Mercado
M L
ML
Calle-Patino
Y
Y
Geller
H M
HM
D000818:Animals; D000831:Animals, Newborn; D000941:Antigens / Q000378:metabolism; D001253:Astrocytes / Q000166:cytology / Q000201:enzymology*; D002273:Carcinogens / Q000494:pharmacology; D002450:Cell Communication / Q000502:physiology; D002460:Cell Line; D004789:Enzyme Activation / Q000502:physiology; D005260:Female; D015151:Immunoblotting; D007527:Isoenzymes / Q000032:analysis / Q000378:metabolism*; D007797:Laminin / Q000378:metabolism; D016501:Neurites / Q000201:enzymology*; D009474:Neurons; D009900:Optic Nerve / Q000166:cytology / Q000254:growth & development; D011247:Pregnancy; D011493:Protein Kinase C / Q000032:analysis / Q000378:metabolism*; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D051744:Protein Kinase C-epsilon; D011509:Proteoglycans / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology; D019063:Tenascin / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D000099216:Chondroitin Sulfate Proteoglycan 4
D000941:Antigens; D002273:Carcinogens; D007527:Isoenzymes; D007797:Laminin; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D051744:Protein Kinase C-epsilon; D011509:Proteoglycans; D019063:Tenascin; D013755:Tetradecanoylphorbol Acetate; D000099216:Chondroitin Sulfate Proteoglycan 4; C121346:laminin 1; C497257:Prkce protein, rat