Figure 4. Multiple strategies for transport with trafficking and cargo detachment controlled by local signals.

(A) Schematic of microtubular transport model with irreversible detachment in a branched morphology. (B) Multiple strategies for trafficking cargo to match local demand (demand = ${\displaystyle {\tilde{u}}^{\star }}$). (Top) The demand-dependent trafficking mechanism (DDT). When the timescale of detachment is sufficiently slow, the distribution of cargo on the microtubules approaches a quasi-steady-state that matches ${\displaystyle {\tilde{u}}^{\star }}$ spatially. This distribution is then transformed into the distribution of detached cargo, ${\displaystyle u^{\star }}$. (Bottom) The demand dependent detachment (DDD) mechanism. Uniform trafficking spreads cargo throughout the dendrites, then demand is matched by slowly detaching cargo according to the local demand signal. An entire family of mixed strategies is achieved by interpolating between DDT and DDD. (C–E) Quasi-steady-state distribution of cargo on the microtubules ($u$, red) and steady-state distribution of detached cargo (${\displaystyle u^{\star }}$, blue), shown with a demand profile (${\displaystyle {\tilde{u}}^{\star }}$, black) for the various strategies diagrammed in panel B. The demand profile is shown spatially in the color-coded CA1 neuron in the right of panel C. Detached cargo matches demand in all cases.

DOI: http://dx.doi.org/10.7554/eLife.20556.009