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Additional file 4: Figure S4. Set up of optogenetic activation of mTORC1 in HeLa cells. A) CIBN-Rab7 was correctly targeted to LEs in HeLa cells transfected with CIBN-myc-Rab7 and immunolabeled for LAMP1 and myc tag. B) Photoactivation was able to target CRY2-mCherry-Raptor to LEs. HeLa cells were transfected with CIBN-myc-Rab7 and CRYII-mCherry-Raptor; 24 h later cells were either kept in the dark (left panel) or photoactivated for 5 min (30 × 100 ms-pulses of blue light given at 0.1 Hz at 2.42 mW/cm2) (right panel) before being processed for immunofluorescence. C) Photoactivation (as in B) was able to target mTOR with CRY2-mCherry-Raptor to LEs. D) Left, clustering of CRY2-mCherry-Raptor on LEs induced by photoactivation reverses within a few min. Shown is an index of raptor clustering (intensity (max/min)/mean) per pixel obtained on raptor surface area). Right, the same treatment induces effective pS6 phosphorylation only 30 min after it was given. Experiments were performed as in (B) with immunofluorescence done at different times after illumination (PA) as indicated. Cells were incubated in culture medium after illumination (N = 90 images per condition from three independent experiments). E) Rapamycin blocks photoactivation-induced P-pS6 increase (N = 90 images per condition from three independent experiments). F) The effect of photoactivation-induced mTOR recruitment to LEs on mTOR activity depends on FCS but only partially relies on amino acids. Cells were fed ( +) or starved (-) with serum (FCS) or amino acids (AA) for the time indicated in the diagram. In AA-starved cells, photoactivation induces an increase in P-pS6, although significantly reduced in comparison to cells fed with both AA and FCS. FCS starvation suppresses mTORC1 activity even after photoactivation (N = 60 images per condition from two independent experiments).

Additional file 3: Figure S3. TrkB inhibitors ANA12 or cyclotraxin-B reduced the recruitment of mTOR to LEs (IN/OUT ratio, see Fig. 3) induced by NMDAR- activation even in starvation conditions. Neurons were treated as in Fig. 3D in ACSF plus Mg2+ or in Mg2+-free ACSF, as indicated A) Effect of ANA12 (25 µM) on mTOR IN/OUT ratio from 3 independent experiments. B) Effect of Cyclotraxin-B (CtxB) on mTOR IN/OUT ratio from 2 independent experiments. In stimulated neurons treated with the TrkB inhibitors, the IN/OUT mTOR ratio stays significantly higher than the one observed in non-stimulated neurons. C) Bafilomycin-A (BafA 200 nM) prevented the translocation of mTOR to LEs triggered by Mg2+ removal as in Fig. 3D (N = 20 images per condition from 2 independent experiments).

Additional file 2: Figure S2. Increased pS6 phosphorylation 90 min after NMDAR stimulation in soma and proximal dendrites. Neurons were treated in cLTP medium as in Fig. 1B with or without AP5 or rapamycin as indicated, then incubated again in conditioned medium (CM) for 80 min before P-pS6 and MAP2 immunofluorescence. Note that over such extended-duration treatments, ACSF was replaced by CM to preserve neuron health. Individual neurons were imaged and P-pS6 quantified in soma or proximal dendrites (mean length 75 µM) for 40–60 neurons from 3 experiments.

Nonlinear optics concerns the modifications of the optical properties of a material induced by the propagation of light. Since its beginnings, fifty years ago, it has already found applications in almost any field of science. In micro and nano-photonics, nonlinear phenomena are at the heart of both fascinating fundamental physics and interesting potential applications: they give a handle to tailor and control the flow of light within a sub-wavelength spatial scale. Indeed, the nonlinear effects can be enhanced in systems allowing tight light confinement and low optical loses. Good candidates for this are the Photonic Crystal (PhC) nanocavities, which have been extensively studied in recent years. Among the great diversity of nonlinear processes in optics, nonlinear dynamical phenomena such as bistability and excitability have recently received considerable attention. While bistability is well known as a building block for all-optical memories, switching and logic gates, excitability has been demonstrated in optics about fifteen years ago: coming from neuroscience, it is the mechanism underlying action potential firing in neurons. In this work, we have studied bistable, self-pulsing and excitable regimes in InP-based PhC nanocavities. In order to achieve efficient light coupling into the nanocavities, we have developed an evanescent coupling technique using tapered optical microfibers. As a result, we have demonstrated for the first time excitability in a PhC nanocavity. In addition, we have accomplished the first step towards nonlinear dynamics in arrays of coupled cavities by demonstrating optical linear coupling between adjacent nanocavitites. This was achieved using far field measurements of photoluminescence. A set of coupled nonlinear resonators opens the door to a rich family of nonlinear dynamical phenomena based on spontaneous symmetry breaking. We have theoretically demonstrated this phenomenon in two evanescently coupled cavities. The first experimental studies on this regime were carried out, which establish a basis for a future demonstration of spontaneous symmetry breaking in arrays of nonlinear coupled PhC nanocavities., L’optique non linéaire traite les modifications des propriétés optiques d'un matériau induites par la propagation de la lumière. Depuis ses débuts, il y a cinquante ans, des nombreuses applications ont été démontrées dans presque tous les domaines de la science. Dans le domaine de la micro et nano-photonique, les phénomènes non linéaires sont à la fois au cœur d’une physique fondamentale fascinante et des applications intéressantes: ils permettent d'adapter et de contrôler le flux de lumière à une échelle spatiale inferieure à la longueur d'onde. En effet, les effets non linéaires peuvent être amplifiés dans des systèmes qui confinent la lumière dans des espaces restreints et avec de faibles pertes optiques. Des bons candidats pour ce confinement sont les nanocavités à cristaux photoniques (CPs), qui ont été largement étudiées ces dernières années. Parmi la grande diversité des processus non linéaires en optique, les phénomènes dynamiques tels que la bistabilité et l'excitabilité font l’objet de nombreuses études. La bistabilité est bien connue pour ces applications potentielles pour les mémoires et les commutateurs optiques et pour les portes logiques. Une réponse excitable typique est celle subjacente dans le déclanchement du potentiel d'action dans les neurones. En optique, l'excitabilité a été observée il y a une quinzaine d’années. Dans ce travail, nous avons étudié les régimes bistables, auto-oscillants et excitables dans des nanocavités semiconductrices III-V à CP. Afin de coupler efficacement la lumière dans les nanocavités, nous avons développé une technique de couplage par onde évanescente en utilisant une microfibre optique étirée. Grâce à cette technique, nous avons démontré pour la première fois l’excitabilité dans une nanocavité à CP. En parallèle, nous avons accompli la première étape vers la dynamique non linéaire dans un réseau de cavités couplées en démontrant le couplage optique linéaire entre nanocavitités adjacentes. Ceci a été réalisé en utilisant de mesures de photoluminescence en champ lointain. Un ensemble de résonateurs non linéaires couplés ouvre la voie à une famille de phénomènes dynamiques non linéaires très riches, basés sur la rupture spontanée de symétrie. Nous avons démontré théoriquement ce phénomène dans deux cavités couplées par onde évanescente. Les premières études expérimentales de ce régime ont été menées, établissant ainsi les bases pour une future démonstration de la rupture spontanée de symétrie dans un réseau de nanocavités non linéaires couplées.