Calyculin-A-induced fast neurite retraction in nerve growth factor-differentiated rat pheochromocytoma (PC12) cells.
Rat pheochromocytoma (PC12) cells were treated with nerve growth factor (NGF) for 3-4 days. They formed growth cones and extended neurites. Addition of the phosphatase inhibitor calyculin A (CL-A) caused a concentration-dependent complete retraction of neurites within 15 min. Retraction of growth cones started with the filopodia still present. The cell bodies acquired a grape-like shape opposite to the cell nucleus. These morphological changes were reversible. After washout of the inhibitor, the cell bodies recovered to normal shape within about 30-60 min while neurites started to grow again within 1 day. Okadaic acid (OA) which, compared to CL-A, is less potent as a PP-1 and equally potent as a PP-2A class inhibitor, caused neurite retraction only when added at more than a thousand-fold higher concentration than CL-A. Ca2+ levels within neurites and cell bodies remained stable and low during neurite retraction as measured with fura-2. However, cells treated with CL-A showed reduced activity of voltage-gated Ca2+ channels. The results suggest that the observed reversible changes in cell morphology occur at a constant low Ca2+ level and are most likely due to the inhibition of PP-1 class phosphatases.
Reber
B F
BF
Department of Pharmacology, University of Bern, Switzerland.
Bouron
A
A
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D003599:Cytoskeleton / Q000187:drug effects; D004988:Ethers, Cyclic / Q000494:pharmacology; D016257:Fura-2; D008387:Marine Toxins; D009414:Nerve Growth Factors / Q000494:pharmacology*; D016501:Neurites / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D019319:Okadaic Acid; D010080:Oxazoles / Q000494:pharmacology*; D016716:PC12 Cells; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D051381:Rats
D004988:Ethers, Cyclic; D008387:Marine Toxins; D009414:Nerve Growth Factors; D010080:Oxazoles; D019319:Okadaic Acid; C059041:calyculin A; D010749:Phosphoprotein Phosphatases; D002118:Calcium; D016257:Fura-2