HEAT repeat proteins

Smith L, Van Hateren N, Siggers P Larder R, Willan J, Walsh J, Arkell A, Greenfield A (2003) Candidate testis determining gene. Maestro (Mro), encodes a novel HEAT repeat protein. Dev Dyn. 227,600-607. 

Ballinger, C. A., P. Connell, Y. Wu, Z. Hu, L. J. Thompson, L. Y. Yin, and C. Patterson. Identification of CHIP, a novel tetratricopeptide repeat-containing protein that interacts with heat shock proteins and negatively regulates chaperone functions. Mol Cell Biol. 19 4535-45.1999. 

Andrade MA, Bork P (1995) HEAT repeats in the Huntington s disease protein. Nat Genet 11 115—116. 

The stimulation of mitochondrial pregnenolone production by adrenal cytosohc fractions has been observed repeatedly [34-38], but has not been adequately characterized. A heat-stable protein preparation has been obtained from adrenal cytoplasm [39] and has been reported to stimulate cholesterol side-chain cleavage by acetone powders of adrenal mitochondria [40]. Cholesterol-binding properties of cytosolic fractions from the adrenal and testis [41] and from ovary [41,42] have also been reported. 

The structure of the middle domain unexpectedly revealed that the eIF4Gs are members of the HEAT repeat family of proteins [named for... 

Kemper WM, Berry KW, Merrick WC (1976) Purification and properties of rabbit reticulocyte protein synthesis initiation factors M2Balpha and M2Bbeta. J Biol Chem 251 5551-5557 Kim SC, Sprung R, Chen Y et al (2006a) Substrate and functional diversity of lysine acetylation revealed by a proteomics survey. Mol Cell 23 607-618 Kim YS, Kang KR, Wolff EC d al (2006b) Deoxyhypusine hydroxylase is a Fe(ll)-dependent, HEAT-repeat enzyme. Identification of amino acid residues critical for Fe(II) binding and catalysis [corrected]. J Biol Chem 281 13217—13225... 

These data do not provide strong support for the heat water stress/urea recycling model (Ambrose 1991). This model may be incorrect or inapplicable to rats. Were the experimental conditions inappropriate, with temperatures too low and/or protein levels too low or too high In the heat stress experiments that inspired this research animals were kept at a temperature of 40°C for 12 hours each day rather than 36°C in this study. In our heat and water stress experiments the protein content of the diets were set at 20% and 70%. These are relatively high levels compared to those in herbivore diets. It would be necessary to repeat the experiments with ruminant herbivores or lower protein diets to conclusively determine if rats are an inappropriate model. 

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