Abstract
Programmed cell death is crucial for developments and responses to various stresses in plants, and is highly regulated by a wide variety of factors. Bax Inhibitor-1 (BI-1) is a widely conserved cell-death suppressor. Arabidopsis BI-1 (AtBI-1) is a 7-times transmembrane protein localized in endoplasmic reticulum (ER), and suppresses cell death induced by oxidative stress, which generates reactive oxygen species (ROS) in plant cells. In addition, calmodulin interacts with the C-terminus of AtBI-1, which is essential for its function. However, the molecular mechanism of BI-1-mediated cell death is still unclear.
We suggested that AtBI-1 interacts with sphingolipid fatty acid metabolic enzymes via an electron transfer protein, cytochrome b5. Sphingolipid has a 2-hydroxylated very-long-chain fatty acid (2-hydroxy VLCFA), and it is implied that AtBI-1 interacts with sphingolipid fatty acid 2-hydroxylases (AtFAH) and VLCFA condensing enzymes (AtELO). Here we show the relationship between AtBI-1 and sphingolipid fatty acid generated by AtFAH and AtELO.
