Amphisome biogenesis, trafficking and signaling at presynaptic boutons
ANNA KARPOVA (Leibniz Institute for Neurobiology (LIN), Magdeburg)
MICHAEL R. KREUTZ (Leibniz Institute for Neurobiology (LIN), Magdeburg)
Autophagosomes fuse with late endosomes in order to undergo robust retrograde transport and we hypothesize that in the absence of autolysosome formation, the resulting amphisomes serve as signaling and sorting platforms while trafficking in a retrograde direction to the cell soma. Accordingly, we could show that the TrkB/LC3/SIPA1L2 amphisome traffics retrogradely along axons, stops at presynaptic boutons and both motility and signaling are controlled by SIPA1L2 whose RapGAP activity reduces the velocity of amphisome trafficking. In this project we will try to understand whether the assembly of amphisomes at boutons is involved in presynaptic plasticity and long-range signaling. Our overarching hypothesis is that the enormous complexity of neuronal cytoarchitecture has led to ways of long-distance protein transport that combine degradative with signaling functions.
We will employ up-to-date methodology including microfluidic devices, CRISPR-CAS9 gene editing in combination with imaging (spinning disk confocal, TIRF, STED) and in-vitro electrophysiology to assess amphisome biogenesis and functions.
References:
Andres-Alonso M, … Stork O, Schweizer M, Gundelfinger ED, Kneussel M, Spilker C, Karpova A*, Kreutz MR* (2019) SIPA1L2 controls trafficking and local signaling of TrkB-containing amphisomes at presynaptic terminals. Nat Commun 10:5448. *co-corresponding authors
Andres-Alonso M, Kreutz MR*, Karpova A* (2020) Autophagy and the endolysosomal system in presynaptic function. Cell Mol Life Sci, *co-corresponding authors
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Mikhaylova M, … Gundelfinger ED, Sharma Y, Kreutz MR. (2009) Calneurons provide a calcium threshold for trans-Golgi network to plasma membrane trafficking. Proc Natl Acad Sci U S A. 106:9093-8.
Karpova A, Mikhaylova M, … Gundelfinger, E.D., Kreutz, M.R. (2013) Encoding and Transducing the Synaptic or Extrasynaptic Origin of NMDA Receptor Signals to the Nucleus. Cell 152(5):1119-1133.
Spilker C, … Kreutz M.R., Gundelfinger E.D. (2008) SPAR2, a novel SPAR-related protein with GAP activity for Rap1 and Rap2. J Neurochem, 104(1): p. 187-201.
Karpova A, Mikhaylova M, Thomas U, Knöpfel T, Behnisch T. (2006) Involvement of protein synthesis and degradation in long-term potentiation of Schaffer Collateral CA1 synapses, J Neurosci 26(18):4949-4955.
