Characterization of the conserved interaction between GATA and FOG family proteins.
The N-terminal zinc finger (ZnF) from GATA transcription factors mediates interactions with FOG family proteins. In FOG proteins, the interacting domains are also ZnFs; these domains are related to classical CCHH fingers but have an His --> Cys substitution at the final zinc-ligating position. Here we demonstrate that different CCHC fingers in the FOG family protein U-shaped contact the N-terminal ZnF of GATA-1 in the same fashion although with different affinities. We also show that these interactions are of moderate affinity, which is interesting given the presumed low concentrations of these proteins in the nucleus. Furthermore, we demonstrate that the variant CCHC topology enhances binding affinity, although the His --> Cys change is not essential for the formation of a stably folded domain. To ascertain the structural basis for the contribution of the CCHC arrangement, we have determined the structure of a CCHH mutant of finger nine from U-shaped. The structure is very similar overall to the wild-type domain, with subtle differences at the C terminus that result in loss of the interaction in vivo. Taken together, these results suggest that the CCHC zinc binding topology is required for the integrity of GATA-FOG interactions and that weak interactions can play important roles in vivo.
School of Molecular and Microbial Biosciences, University of Sydney, Sydney New South Wales 2006, Australia.
Kasper
K
Kowalski
Chu Kong
CK
Liew
Jacqueline M
JM
Matthews
David A
DA
Gell
Merlin
M
Crossley
Joel P
JP
Mackay
D000595:Amino Acid Sequence; D017124:Conserved Sequence; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D016335:Zinc Fingers
D014157:Transcription Factors