E-Letter responses to:

reports: Siobán B. Keel, Raymond T. Doty, Zhantao Yang, John G. Quigley, Jing Chen, Sue Knoblaugh, Paul D. Kingsley, Ivana De Domenico, Michael B. Vaughn, Jerry Kaplan, James Palis, and Janis L. Abkowitz A Heme Export Protein Is Required for Red Blood Cell Differentiation and Iron Homeostasis Science 2008; 319: 825-828 [Abstract] [Full text] [PDF]

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Heme-Controlled Protein Synthesis

Heikki Savolainen   (25 March 2008)

Heme-Controlled Protein Synthesis 25 March 2008
Heikki Savolainen, Professor Department of Occupational Safety and Health, Tampere, Finland Respond to this E-Letter: Re: Heme-Controlled Protein Synthesis	In regard to S. B. Keel et al.’s Report ("A heme export protein is required for red blood cell differentiation and iron homeostasis," 8 February 2008, p. 825), the incorporation of freshly synthesized heme in the hemoprotein molecules is only one of its many regulatory roles. It also seems to restart protein synthesis in rat circulating reticulocytes after a histotoxic insult (1). This is mediated by a heme-stabilized translational inhibitor (2). The system depends on a redox cycle catalyzed by thioredoxin (1). The heme iron must be in a ferrous state and free iron ions are not substrates. Therefore, it seems that using heme as an independent therapeutic agent opens up very promising vistas. Heikki Savolainen Department of Occupational Safety and Health, Tampere, Finland. References 1. H. Savolainen et al., Res. Commun. Chem. Path Pharmacol. 50, 245 (1985). 2. C. Palomo et al. Arch. Biochem. Biophys. 239, 497 (1985).