InterPro domain: IPR001313

Members of the Pumilio family of proteins (Puf) regulate translation and mRNA stability in a wide variety of eukaryotic organisms including mammals, flies, worms, slime mold, and yeast [ 1 ]. Pumilio family members are characterised by the presence of eight tandem copies of an imperfectly repeated 36 amino acids sequence motif, the Pumilio repeat, surrounded by a short N- and C-terminal conserved region. The eight repeats and the N- and C-terminal regions form the Pumilio homology domain (PUM-HD). The PUM-HD domain is a sequence-specific RNA binding domain. The Puf family of proteins are mainly post-transcriptional regulators. Several Puf members have been shown to bind specific RNA sequences mainly found in the 3' UTR of mRNA and repress their translation [ 2 , 3 ]. Frequently, Puf proteins function asymmetrically to create protein gradients, thus causing asymmetric cell division and regulating cell fate specification [ 4 ].

Crystal structure of Pumilio repeats has been solved [ 5 ]. The PUM repeat with the N- and C-terminal regions pack together to form a right-handed superhelix that approximates a half doughnut structurally similar to the Armadillo (ARM) repeat proteins, beta-catenin andkaryopherin alpha. The RNA binds the concave surface of the molecule, whereeach of the protein's eight repeats makes contacts with a different RNA basevia three amino acid side chains at conserved positions [ 6 ].

This entry represents the Pumilio repeat.

1. Translational repression: a duet of Nanos and Pumilio. Curr. Biol. 10, R81-3
2. The PUF family of RNA-binding proteins: does evolutionarily conserved structure equal conserved function? IUBMB Life 55, 359-66
3. The PUF Protein Family: Overview on PUF RNA Targets, Biological Functions, and Post Transcriptional Regulation. Int J Mol Sci 19
4. Pumilio is essential for function but not for distribution of the Drosophila abdominal determinant Nanos. Genes Dev. 6, 2312-26
5. Crystal structure of a Pumilio homology domain. Mol. Cell 7, 855-65
6. Modular recognition of RNA by a human pumilio-homology domain. Cell 110, 501-12