Étienne Labrie-Dion

EMAIL:

POSITION:

M.Sc. student in Neurobiology, Université Laval (http://www.ulaval.ca)

ACADEMIA:

B.Sc. in Biology, Université Laval (http://www.ulaval.ca)

ADVISORS:

Paul De Koninck (http://www.greenspine.ca)

RESEARCH INTERESTS:

Live imaging of growth cones

betaCaMKII dynamics in the axonal growth cone

Research Summary

The ability of neurons to form complex networks and specific connections is a fundamental problem that is poorly understood. One initial process involves the path finding of neuronal growth cones. Upon detection of chemical cues, a major secondary signal is the generation of calcium oscillations in the growth cone. It is known that the Ca2+/calmodulin dependent protein kinase II (CaMKII) regulates growth cone turning, although the underlying mechanism remains unclear. Recently, we have shown that CaMKII binds to microtubules in an activity-dependent manner in cultured neurons. Furthermore, it has been shown that betaCaMKII also binds to filamentous actin (F-actin), thereby regulating axonal and dendritic arborisation during neuronal development. In contrast to its microtubule binding, CaMKII is released from F-actin during calcium elevation. Because growth cone dynamics require constant remodelling of F-actin and microtubules, we hypothesize that these processes are regulated by CaMKII interactions. To monitor CaMKII dynamics in growth cones in cultured hippocampal neurons, we use high spatial and temporal imaging of genetically encoded labels, such as XFP-tagged betaCaMKII, Lifeact (F-actin), tubulin, and EB3 (microtubules). By combining these approaches with the use of pharmacological, peptidic and genetic means of regulating CaMKII, we have preliminary evidence that betaCaMKII plays an important role in growth cones. Our results suggest that CaMKII decodes calcium oscillations and regulates microtubules and actin filaments dynamics.