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. 2014 Oct 30;10(11):2079–2081. doi: 10.4161/auto.34451

Figure 1.

Figure 1.

MAPK8IP 1 regulates the axonal transport of 2 different organelles, APP-positive vesicles and autophagosomes. (A) MAPK8IP 1 exists as 2 distinct motor complexes—an anterograde complex binds directly to KIF5 and activates kinesin motor activity, and a retrograde complex binds directly to the dynein activator dynactin. Phosphorylation at the S421 site in the KIF5-binding domain of MAPK8IP 1 regulates switching between these 2 complexes and, thus, determines the direction of APP transport. (B) Two mechanisms ensure that autophagosomes move exclusively in the retrograde direction in the axon. The phosphatase DUSP1, which robustly associates with MAPK8IP 1-positive autophagosomes, may maintain MAPK8IP 1 in the nonphosphorylated retrograde motor complex. Binding of LC3 to MAPK8IP 1 further deters binding and activation of KIF5. MT, microtubule.