Belmonte, C. | Search bioRxiv

bioRxiv2025

In vivo Morphological Dynamics of Single Laser-Axotomized Corneal Nerve Fibers in Sarm1-Null Adult Mice

Axonal regeneration represents a pivotal aspect of the adult peripheral nervous system (PNS). When an injury occurs, peripheral axons are able to regenerate and reestablish connections with their original targets. Although several precision techniques for severing axons in various non-mammalian model organisms have allowed to study the dynamics of regeneration after injury, similar axonal injury models have yet to be fully developed in mammals. In this study, we introduced a novel experimental method for laser-induced axotomy of single corneal sensory subbasal nerve fibers. This method enables the in vivo monitoring and quantification of axonal degeneration and regeneration morphological dynamics in adult mice. Results revealed that the degeneration of the distal stump of the subbasal fiber was delayed in mice lacking the protein SARM1, which promotes degenerative process after injury. Meanwhile, the proximal stump maintained the regenerative dynamics of the subbasal fiber, but regeneration of its nerve terminals was impaired. The present study introduces a valuable model for the in vivo study of the morphological plasticity dynamics of peripheral axons after injury in genetically tractable adult mammals.

neuroscience↗

bioRxiv2020

The P4-ATPase Drs2 regulates the homeostasis of Atg9

Multisubunit Tethering Complexes (MTCs) are a set of conserved protein complexes that tether transported vesicles at the acceptor membrane. Interactions with other components of the trafficking machinery regulate MTCs through mechanisms that are just partially understood. Here we systematically investigate the interactome that regulates the function of MTCs. We found that P4-ATPases, a family of lipid transporters involved in the biogenesis of vesicles, interact with MTCs that participate in the anterograde and retrograde transport at the Golgi, such as TRAPPIII. We used the lipid flippase Drs2 as a model to investigate the mechanism and biological relevance of such interplay during the transport of Atg9 vesicles. Binding to the N-terminal tail of Drs2 stabilizes TRAPPIII on membrane compartments loaded with Atg9 and it is required for the delivery of Atg9 during selective autophagy, a role that is independent of previously reported functions of the P4-ATPase. This mechanism relies on the I(S/R)TTK motif nested in the N-terminal tail cavity of Drs2, a motif that is required for the interaction with MTCs.

cell biology↗