NMR structure and mutagenesis of the FADD (Mort1) death-effector domain.
When activated, membrane-bound receptors for Fas and tumour-necrosis factor initiate programmed cell death by recruiting the death domain of the adaptor protein FADD to the membrane. FADD then activates caspase 8 (also known as FLICE or MACH) through an interaction between the death-effector domains of FADD and caspase 8. This ultimately leads to the apoptotic response. Death-effector domains and homologous protein modules known as caspase-recruitment domains have been found in several proteins and are important regulators of caspase (FLICE) activity and of apoptosis. Here we describe the solution structure of a soluble, biologically active mutant of the FADD death-effector domain. The structure consists of six antiparallel, amphipathic alpha-helices and resembles the overall fold of the death domains of Fas and p75. Despite this structural similarity, mutations that inhibit protein-protein interactions involving the Fas death domain have no effect when introduced into the FADD death-effector domain. Instead, a hydrophobic region of the FADD death-effector domain that is not present in the death domains is vital for binding to FLICE and for apoptotic activity.
Eberstadt
M
M
Pharmaceutical Discovery Division, Abbott Laboratories, Abbott Park, Illinois 60064, USA.
Huang
B
B
Chen
Z
Z
Meadows
R P
RP
Ng
S C
SC
Zheng
L
L
Lenardo
M J
MJ
Fesik
S W
SW
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D017209:Apoptosis; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; D018360:Crystallography, X-Ray; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000378:metabolism; D053200:Fas-Associated Death Domain Protein; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D019014:fas Receptor / Q000737:chemistry
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D053200:Fas-Associated Death Domain Protein; D019014:fas Receptor; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; D003546:Cysteine Endopeptidases