RT Journal Article
SR Electronic
T1 Axon terminals control endolysosome diffusion to support synaptic remodelling
JF Life Science Alliance
JO Life Sci. Alliance
FD Life Science Alliance LLC
SP e202101105
DO 10.26508/lsa.202101105
VO 4
IS 8
A1 Beatrice Terni
A1 Artur Llobet
YR 2021
UL https://www.life-science-alliance.org/content/4/8/e202101105.abstract
AB Endolysosomes are acidic organelles formed by the fusion of endosomes with lysosomes. In the presynaptic compartment they contribute to protein homeostasis, the maintenance of vesicle pools and synaptic stability. Here, we evaluated the mobility of endolysosomes found in axon terminals of olfactory sensory neurons of Xenopus tropicalis tadpoles. F-actin restricts the motion of these presynaptic acidic organelles which is characterized by a diffusion coefficient of 6.7 × 10−3 μm2·s−1. Local injection of secreted protein acidic and rich in cysteine (SPARC) in the glomerular layer of the olfactory bulb disrupts the structure of synaptic F-actin patches and increases the presence and mobility of endolysosomal organelles found in axon terminals. The increased motion of endolysosomes is localized to the presynaptic compartment and does not promote their access to axonal regions for retrograde transportation to the cell body. Local activation of synaptic degradation mechanisms mediated by SPARC coincides with a loss of the ability of tadpoles to detect waterborne odorants. Together, these observations show that the diffusion of presynaptic endolysosomes increases during conditions of synaptic remodelling to support their local degradative activity.