Bax inhibitor-1: a highly conserved endoplasmic reticulum-resident cell death suppressor

Cell Death Differ. 2011 Aug;18(8):1271-8. doi: 10.1038/cdd.2011.59. Epub 2011 May 20.


In spite of fundamental differences between plant and animal cells, it is remarkable that some cell death regulators that were identified to control cell death in metazoans can also function in plants. The fact that most of these proteins do not have structural homologs in plant genomes suggests that they may be targeting a highly conserved 'core' mechanism with conserved functions that is present in all eukaryotes. The ubiquitous Bax inhibitor-1 (BI-1) is a common cell death suppressor in eukaryotes that has provided a potential portal to this cell death core. In this review, we will update the current status of our understanding on the function and activities of this intriguing protein. Genetic, molecular and biochemical studies have so far suggested a consistent view that BI-1 is an endoplasmic reticulum (ER)-resident transmembrane protein that can interact with multiple partners to alter intracellular Ca(2+) flux control and lipid dynamics. Functionally, the level of BI-1 protein has been hypothesized to have the role of a rheostat to regulate the threshold of ER-stress inducible cell death. Further, delineation of the cell death suppression mechanism by BI-1 should shed light on an ancient cell death core-control pathway in eukaryotes, as well as novel ways to improve stress tolerance.

Publication types

  • Review

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins / metabolism
  • Calcium / metabolism
  • Calmodulin / genetics
  • Calmodulin / metabolism
  • Cell Death / physiology*
  • Endoplasmic Reticulum / metabolism*
  • Homeostasis
  • Humans
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Plant Cells
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Plants / genetics
  • Plants / metabolism
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Signal Transduction / physiology
  • bcl-2-Associated X Protein / antagonists & inhibitors*
  • bcl-2-Associated X Protein / metabolism


  • Apoptosis Regulatory Proteins
  • Calmodulin
  • Membrane Proteins
  • Plant Proteins
  • Protein Isoforms
  • TMBIM6 protein, human
  • bcl-2-Associated X Protein
  • Calcium