VAPB and YIF1A regulate membrane delivery into dendrites

Marijn Kuijpers, Ka Lou Yu, Eva Teuling, Anna Akhmanova, Dick Jaarsma and Casper C. Hoogenraad. The ALS8 protein VAPB interacts with the ER–Golgi recycling protein YIF1A and regulates membrane delivery into dendrite. The EMBO Journal advance online publication 04 June 2013; doi:10.1038/emboj.2013.131

The vesicle-associated membrane protein (VAMP) associated protein B (VAPB) is an integral membrane protein localized to the endoplasmic reticulum (ER). The P56S mutation in VAPB has been linked to motor neuron degeneration in amyotrophic lateral sclerosis type 8 (ALS8) and forms ER-like inclusions in various model systems. However, the role of wildtype and mutant VAPB in neurons is poorly understood. Here, we identified Yip-1 interacting factor homolog A (YIF1A) as a new VAPB binding partner and important component in the early secretory pathway. YIF1A interacts with VAPB via its transmembrane regions, recycles between the ER and Golgi and is mainly localized to the endoplasmic reticulum – Golgi intermediate compartments (ERGIC) in rat hippocampal neurons. VAPB strongly affects the distribution of YIF1A and is required for intracellular membrane trafficking into dendrites and normal dendritic morphology. When VAPB-P56S is present, YIF1A is recruited to the VAPB-P56S clusters and loses its ERGIC localization. These data suggest that both VAPB and YIF1A are important for ER-to-Golgi transport and that missorting of YIF1A may contribute to VAPB associated motor neuron disease.