The endoplasmic reticulum (ER) is the organelle for processing proteins for cellular activity. It synthesizes lipids and secrets modified proteins that are checked to see if folded properly from the ER membrane to the many other organelles in the cell. Because membrane proteins are bound by the cytosol's lattice structure, their diffusion is entirely dependent on the ER exit sites. Because of this, the clear pathway of the ER is vital for proper sorting and movement of proteins. The reticular pattern of the ER is highly dependent on the microtubule network of motor and non-motor proteins. Specifically non motor proteins, VAMP-associated proteins (VAPs) anchor the ER membrane to microtubules for support. Disruption of these proteins can lead to the collapse of the peripheral ER tubules allowing immobile obstacles to form which obstruct the passage of proteins from the ER membrane.

Among the VAPs there are two different VAP genes in humans. The A isoform (VAPA) and B isoform (VAPB) are membrane proteins and are structurally similar with an N-terminal major sperm protein. Among these VAPs, specifically VAPB there is a mutation linked to the late-onset form of amyotrophic lateral sclerosis (ALS8). The P56S mutation introduces a kink between β strands, causing aggregation to occur in the ER. Although this mutation is linked to ALS8, both isoforms are expressed suggesting they are required for cell survival.

While the VAPs perform necessary functions, they also work with other proteins and cause interactions that can be beneficial for cellular processes. One of these beneficial interactions is with the FFAT (two phenylalanines in an acidic tract) motif, which will help with inhibiting the dire effects of the P56S mutation. The motif interacts with the MSP domain of the VAP proteins allowing lipid binding proteins to make it to the cytosolic surface of the ER.

To test the effects of the FFAT motif, and learn about the normal processes of VAPA and VAPB, each isoform was over-expressed and viewed under many different experiments for their processes with transmembrane proteins, soluble proteins, and microtubules.