Prof. Sima Lev’ team showed that the three Nir proteins interact with VAP-B, but each interaction affects the structural integrity of the ER membranes differently. Whereas the Nir2-VAP-B interaction induces the formation of stacked ER membrane arrays as demonstrated by electron microscopy analysis, the Nir3-VAP-B interaction leads to a gross remodeling of the ER and the bundling of thick microtubules along the altered ER membranes. In contrast, the Nir1-VAP-B interaction has no apparent effect on ER structure.
