Underphosphorylated BAD Interacts With Diverse Antiapoptotic Bcl-2 Family Proteins to Regulate Apoptosis

Apoptosis. 2001 Oct;6(5):319-30. doi: 10.1023/a:1011319901057.


Survival factors activate kinases which, in turn, phosphorylate the proapoptotic Bcl-xl/Bcl-2-associated death promoter homolog (BAD) protein at key serine residues. Phosphorylated BAD interacts with 14-3-3 proteins, and overexpression of 14-3-3 attenuates BAD-mediated apoptosis. Although BAD is known to interact with Bcl-2, Bcl-w, and Bcl-xL, the exact relationship between BAD and anti- or proapoptotic Bcl-2 proteins has not been analyzed systematically. Using the yeast two-hybrid protein interaction assay, we found that BAD interacted negligibly with proapoptotic Bcl-2 proteins. Even though wild type BAD only interacted with selected numbers of antiapoptotic proteins, underphosphorylated mutant BAD interacted with all antiapoptotic Bcl-2 proteins tested (Bcl-2, Bcl-w, Bcl-xL, Bfl-1/A1, Mcl-1, Ced-9, and BHRF-1). Using nonphosphorylated recombinant BAD expressed in bacteria, direct interactions between BAD and diverse antiapoptotic Bcl-2 members were also observed. Furthermore, apoptosis induced by BAD was blocked by coexpression with Bcl-2, Bcl-w, and Bfl-1. Comparison of BAD orthologs from zebrafish to human indicated the conservation of a 14-3-3 binding site and the BH3 domain during evolution. Thus, highly conserved BAD interacts with diverse antiapoptotic Bcl-2 members to regulate apoptosis.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 14-3-3 Proteins
  • Amino Acid Sequence
  • Animals
  • Apoptosis*
  • Binding Sites
  • CHO Cells
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Carrier Proteins / physiology*
  • Conserved Sequence
  • Cricetinae
  • Escherichia coli / genetics
  • Evolution, Molecular
  • Humans
  • Molecular Sequence Data
  • Phosphorylation
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Sequence Homology, Amino Acid
  • Transfection
  • Two-Hybrid System Techniques
  • Tyrosine 3-Monooxygenase / metabolism
  • Yeasts / genetics
  • Zebrafish Proteins
  • bcl-Associated Death Protein


  • 14-3-3 Proteins
  • BAD protein, human
  • Carrier Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Zebrafish Proteins
  • badb protein, zebrafish
  • bcl-Associated Death Protein
  • Tyrosine 3-Monooxygenase