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Updated: Apr 11, 2026

Labeling F-actin Barbed Ends with Rhodamine-actin in Permeabilized Neuronal Growth Cones
Published on: March 17, 2011
Possible role of cortactin phosphorylation by protein kinase Cα in actin-bundle formation at growth cone
Hiroshi Yamada1,2, Tatsuya Kikuchi1, Toshio Masumoto3
1Department of Neuroscience, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Kita-ku, Okayama, 700-8558, Japan.
Background Information:
Cortactin contributes to growth cone morphogenesis by forming with dynamin, ring-shaped complexes that mechanically bundle and stabilise F-actin. However, the regulatory mechanism of cortactin action is poorly understood.
Results:
Immunofluorescence microscopy revealed that protein kinase C (PKC) α colocalises with cortactin at growth cone filopodia in SH-SY5Y neuroblastoma cells. PKC activation by phorbol 12-myristate 13-acetate causes cortactin phosphorylation, filopodial retraction and F-actin-bundle loss. Moreover, PKCα directly phosphorylates cortactin in vitro at S135/T145/S172, mitigating both cortactin's actin-binding and actin-crosslinking activity, whereas cellular expression of a phosphorylation-mimetic cortactin mutant hinders filopodial formation with a significant decrease of actin bundles.
Conclusions:
Our results indicate that PKC-mediated cortactin phosphorylation might be implicated in the maintenance of growth cone.
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