Endoplasmic Reticulum

By Natalia Gurule, PhD

By Christina Towers, PhD.

ARF1 (ADP-ribosylation factor 1) is a protein in the ARF gene family that is responsible for vesicular trafficking within the cell through its activation of phospholipase D. It is found in the cells golgi apparatus and its main function is intra-Golgi transport within the cell. Arf1 is a GTP-binding protein and is known to activate ArfGEF (guanine nucleotide exchange factor) which is a cholera toxin catalytic subunit.

Inositol Requiring Enzyme 1 alpha (IRE1 alpha) is a transmembrane-RNase with an endoplasmic reticulum (ER) luminal sensor domain and cytosolic kinase and ribonuclease domains. IRE1 also plays a central role in the ER stress response (1).

Disulfide bond formation is a pivotal step in the maturation and release of secretory proteins that are controlled by specific endoplasmic reticulum (ER) resident enzymes. An important element in this process is ERO (ER oxidoreduction), a glycosylated flavoenzyme tightly associated with oxidative protein folding that lacks the known ER retention motifs.