InterPro domain: IPR001293

Zinc finger (Znf) domains are relatively small protein motifs which contain multiple finger-like protrusions that make tandem contacts with their target molecule. Some of these domains bind zinc, but many do not; instead binding other metals such as iron, or no metal at all. For example, some family members form salt bridges to stabilise the finger-like folds. They were first identified as a DNA-binding motif in transcription factor TFIIIA from Xenopus laevis (African clawed frog), however they are now recognised to bind DNA, RNA, protein and/or lipid substrates [ 1 , 2 , 3 , 4 , 5 ]. Their binding properties depend on the amino acid sequence of the finger domains and of the linker between fingers, as well as on the higher-order structures and the number of fingers. Znf domains are often found in clusters, where fingers can have different binding specificities. There are many superfamilies of Znf motifs, varying in both sequence and structure. They display considerable versatility in binding modes, even between members of the same class (e.g. some bind DNA, others protein), suggesting that Znf motifs are stable scaffolds that have evolved specialised functions. For example, Znf-containing proteins function in gene transcription, translation, mRNA trafficking, cytoskeleton organisation, epithelial development, cell adhesion, protein folding, chromatin remodelling and zinc sensing, to name but a few [ 6 ]. Zinc-binding motifs are stable structures, and they rarely undergo conformational changes upon binding their target.

This entry represents TRAF-type zinc finger domains. Some of the proteins that have this domain are mammalian signal transducers associated with the cytoplasmic domain of the 75kDa tumour necrosis factor receptor [ 7 ]. A heterocomplex, homodimer or heterodimer of TRAF1 and TRAF2, binds to the N-terminal of the inhibitor of apoptosis proteins 1 and 2 (IAPS) and recruits them to the tumour necrosis factor receptor 2. Other proteins containing this domain include F45G2.6 protein from Caenorhabditis elegans and DG17 protein from Dictyostelium discoideum (Slime mold).

1. Zinc finger peptides for the regulation of gene expression. J. Mol. Biol. 293, 215-8
2. Multiple modes of RNA recognition by zinc finger proteins. Curr. Opin. Struct. Biol. 15, 367-73
3. Zinc finger proteins: getting a grip on RNA. Curr. Opin. Struct. Biol. 15, 94-8
4. Sticky fingers: zinc-fingers as protein-recognition motifs. Trends Biochem. Sci. 32, 63-70
5. Zinc fingers--folds for many occasions. IUBMB Life 54, 351-5
6. Zinc finger proteins: new insights into structural and functional diversity. Curr. Opin. Struct. Biol. 11, 39-46
7. Tumor necrosis factor receptor-associated factors (TRAFs). Oncogene 20, 6482-91