Live-imaging of PKC Translocation in Sf9 Cells and in Aplysia Sensory Neurons
Summary
In this video, we demonstrate visualization of PKC translocation in living cells using fluorescently tagged PKCs.
Abstract
Protein kinase Cs (PKCs) are serine threonine kinases that play a central role in regulating a wide variety of cellular processes such as cell growth and learning and memory. There are four known families of PKC isoforms in vertebrates: classical PKCs (α, βI, βII and γ), novel type I PKCs (ε and η), novel type II PKCs (δ and θ), and atypical PKCs (ζ and ι). The classical PKCs are activated by Ca2+ and diacylclycerol (DAG), while the novel PKCs are activated by DAG, but are Ca2+-independent. The atypical PKCs are activated by neither Ca2+ nor DAG. In Aplysia californica, our model system to study memory formation, there are three nervous system specific PKC isoforms one from each major class, namely the conventional PKC Apl I, the novel type I PKC Apl II and the atypical PKC Apl III. PKCs are lipid-activated kinases and thus activation of classical and novel PKCs in response to extracellular signals has been frequently correlated with PKC translocation from the cytoplasm to the plasma membrane. Therefore, visualizing PKC translocation in real time in live cells has become an invaluable tool for elucidating the signal transduction pathways that lead to PKC activation. For instance, this technique has allowed for us to establish that different isoforms of PKC translocate under different conditions to mediate distinct types of synaptic plasticity and that serotonin (5HT) activation of PKC Apl II requires production of both DAG and phosphatidic acid (PA) for translocation 1-2. Importantly, the ability to visualize the same neuron repeatedly has allowed us, for example, to measure desensitization of the PKC response in exquisite detail 3. In this video, we demonstrate each step of preparing Sf9 cell cultures, cultures of Aplysia sensory neurons have been described in another video article 4, expressing fluorescently tagged PKCs in Sf9 cells and in Aplysia sensory neurons and live-imaging of PKC translocation in response to different activators using laser-scanning microscopy.
Protocol
Discussion
We have described a technique to image translocation of fluorescently tagged PKCs in real time in Sf9 cells and in Aplysia sensory neurons. Sf9 cells provide a simple system to image PKC translocation since culturing and transfecting them is pretty straight-forward. In contrast, microinjection of Aplysia sensory neurons takes some time to master; up to a few months. Difficulties related to this technique include electrode clogging. Filtering the injection solution and centrifuging it usually helps but s…
Disclosures
The authors have nothing to disclose.
Acknowledgements
This work was supported by Canadian Institutes of Health Research (CIHR) Grant to Wayne S. Sossin. Carole A. Farah is the recipient of a postdoctoral fellowship from the Fonds de la Recherche en Santé du Québec (FRSQ) and a Conrad Harrington fellowship. The authors would like to thank Joanna Bougie, Margaret Hastings and Margaret Labban for help with the video shoot and Madeline Richmond Pool for help with the graphic overview.
Materials
| Material Name | Type | Company | Catalogue Number | Comment |
|---|---|---|---|---|
| Sf9 frozen cells | Spodoptera frugiperda ovarian cells | Invitrogen | B825-01 | |
| Grace’s Insect Medium, Supplemented (1X), liquid | Reagent | Gibco | 11605-094 | Use to culture Sf9 cells |
| Corning 75cm2 canted neck cell culture flask | Tool | Corning | 430720 | Use to culture Sf9 cells |
| Fetal Bovine Serum | Reagent | CanSera | CS-C08-500 | Supplement Grace’s media with FBS prior to use |
| Syringe | Tool | Becton Dickinson | 309604 | Use to filter Fast Green solution |
| Syringe | Tool | Becton Dickinson | 309602 | Use to filter plasmid DNA / Fast Green solution |
| Filter | Tool | Corning | 431229 | Use to filter Fast Green solution |
| Filter | Tool | Corning | 431212 | Use to filter plasmid DNA / Fast Green solution |
| Glass Bottom Dish | Tool | Mattek | P35G-1.5-14-C | Use to culture Sf9 cells prior to transfection and imaging |
| Cellfectin II Reagent | Reagent | Invitrogen | 10362-100 | Used to express fluorescently tagged PKCs in Sf9 cells |
| Fast Green FCF | Reagent | Sigma-Aldrich | F-7252 | Use to visualize microinjection of plasmid DNA solution into Aplysia sensory neurons |
| Thin wall glass capillaries | Tool | World Precision Instruments | TW100F-4 | Use to make microelectrodes for microinjection |
| Microloader pipette tip | Tool | Eppendorf | CA32950-050 | Autoclave before using to fill up the microelectrodes for microinjection |
| PV820 Pneumatic PicoPump | Tool | World Precision Instruments | SYS-PV820 | Part of microinjection station |
| Microelectrode holder | Tool | World Precision Instruments | MPH6S | Use to hold microelectrode |
| Micromanipulator | Tool | Sutter | MP-85 | Use to position microelectrode in the three-axis |
References
- Farah, C. A., Nagakura, I., Weatherill, D., Fan, X. &. a. m. p. ;. a. m. p., Sossin, W. S. Physiological role for phosphatidic acid in the translocation of the novel protein kinase C Apl II in Aplysia neurons. Mol Cell Biol. 28, 4719-4733 (2008).
- Zhao, Y., Leal, K., Abi-Farah, C., Martin, K. C., Sossin, W. S. &. a. m. p. ;. a. m. p., Klein, . M.Isoform specificity of PKC translocation in living Aplysia sensory neurons and a role for Ca2+-dependent PKC APL I in the induction of intermediate-term facilitation. J Neurosci. 26, 8847-8856 (2006).
- Farah, C. A., Weatherill, D., Dunn, T. W. &. a. m. p. ;. a. m. p., Sossin, W. S. PKC differentially translocates during spaced and massed training in Aplysia. J Neurosci. 29, 10281-10286 (2009).
- Zhao, Y., Wang, D. O., Martin, K. C. Preparation of Aplysia sensory-motor neuronal cell cultures. J Vis Exp. , (2009).
- Manseau, F., Fan, X., Hueftlein, T., Sossin, W. S., Castellucci, V. F. Ca2+-independent PKC Apl II mediates the serotonin induced facilitation at depressed synapses in Aplysia. J. Neuroscience. 21, 1247-1256 (2001).
