Evidence for crucial electrostatic interactions between Bcl-2 homology domains BH3 and BH4 in the anti-apoptotic Nr-13 protein.
Nr-13 is an anti-apoptotic member of the Bcl-2 family previously shown to interact with Bax. The biological significance of this interaction was explored both in yeast and vertebrate cells and revealed that Nr-13 is able to counteract the pro-apoptotic activity of Bax. The Bax-interacting domain has been identified and corresponds to alpha-helices 5 and 6 in Nr-13. Site-directed mutagenesis has revealed that the N-terminal region of Nr-13 is essential for activity and corresponds to a genuine Bcl-2 homology domain (BH4). The modelling of Nr-13, based on its similarity with other Bcl-2 family proteins and energy minimization, suggests the possibility of electrostatic interactions between the two N-terminal-conserved domains BH4 and BH3. Disruption of these interactions severely affects Nr-13 anti-apoptotic activity. Together our results suggest that electrostatic interactions between BH4 and BH3 domains play a role in the control of activity of Nr-13 and a subset of Bcl-2 family members.
Lalle
Philippe
P
Institut de Biologie et Chimie des Protéines, UMR 5086 CNRS/Université Claude Bernard Lyon 1, 7 passage du Vercors, 69367 Lyon Cedex 07, France.
Aouacheria
Abdel
A
Dumont-Miscopein
Agnès
A
Jambon
Martin
M
Venet
Séverine
S
Bobichon
Hélène
H
Colas
Pierre
P
Deléage
Gilbert
G
Geourjon
Christophe
C
Gillet
Germain
G
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D030161:Avian Proteins; D019556:COS Cells; D002478:Cells, Cultured; D002645:Chickens; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics; D051379:Mice; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000737:chemistry*; D051381:Rats; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D013347:Subcellular Fractions
D030161:Avian Proteins; D008565:Membrane Proteins; C093264:NR13 protein, avian; D019253:Proto-Oncogene Proteins c-bcl-2