Heme: a versatile signaling molecule controlling the activities of diverse regulators ranging from transcription factors to MAP kinases.
Heme (iron protoporphyrin IX) is an essential molecule for numerous living organisms. Not only does it serve as a prosthetic group in enzymes, it also acts as a signaling molecule that controls diverse molecular and cellular processes ranging from signal transduction to protein complex assembly. Deficient heme synthesis or function impacts the hematopoietic, hepatic and nervous systems in humans. Recent studies have revealed a series of heme-regulated transcription factors and signal transducers including Hap1, a heme-activated transcription factor that mediates the effects of oxygen on gene transcription in the yeast Saccharomyces cerevisiae; Bach1, a transcriptional repressor that is negatively regulated by heme in mammalian cells; IRR, an iron regulatory protein that mediates the iron-dependant regulation of heme synthesis in the bacterium Bradyrhizobium japonicum; and heme-regulated inhibitor, an eucaryotic initiation factor 2alpha kinase that coordinates protein synthesis with heme availability in reticulocytes. In this review, we summarize the current knowledge about how heme controls the activity of these transcriptional regulators and signal transducers, and discuss diseases associated with defective heme synthesis, degradation and function.
Mense
Sarah M
SM
Department of Environmental Health Sciences, Columbia University, Mailman School of Public Health, New York, NY 10032, USA.
Zhang
Li
L
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors / Q000378:metabolism; D020369:Bradyrhizobium / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D051856:Fanconi Anemia Complementation Group Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006418:Heme / Q000235:genetics / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D018631:ras Proteins / Q000378:metabolism
C102108:BACH1 protein, human; D001426:Bacterial Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D051856:Fanconi Anemia Complementation Group Proteins; D005656:Fungal Proteins; C058452:HAP1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D006418:Heme; D007501:Iron; D051547:Heme Oxygenase-1; D020928:Mitogen-Activated Protein Kinases; D018631:ras Proteins; D010100:Oxygen