Figure 3.

Intracellular traffics of HO-1. (A) HO-1 variants. (B) The localization of HO-1. After synthesis, the HO-1 protein is delivered to and anchored at the smooth endoplasmic reticulum (ER) membrane. HO-1 can be trafficked to the mitochondria and nucleus under stress or pathological conditions. In the mitochondria, HO-1 affects the mitochondrial biogenesis and dynamics. Mitochondrial HO-1 also increase Fe²⁺ levels and ROS generation, leading to mitophagy. The full-length and truncated form of HO-1 (t-HO-1) are found in the nucleus, in which it regulates gene expressions involved in angiogenesis, anti-apoptotic proteins, anti-oxidative enzymes, metastasis, and mitochondrial biogenesis. The 14 kDa HO-1 variant is retained in the cytosol.