Identification of the Mitochondrial Heme Metabolism Complex.
Heme is an essential cofactor for most organisms and all metazoans. While the individual enzymes involved in synthesis and utilization of heme are fairly well known, less is known about the intracellular trafficking of porphyrins and heme, or regulation of heme biosynthesis via protein complexes. To better understand this process we have undertaken a study of macromolecular assemblies associated with heme synthesis. Herein we have utilized mass spectrometry with coimmunoprecipitation of tagged enzymes of the heme biosynthetic pathway in a developing erythroid cell culture model to identify putative protein partners. The validity of these data obtained in the tagged protein system is confirmed by normal porphyrin/heme production by the engineered cells. Data obtained are consistent with the presence of a mitochondrial heme metabolism complex which minimally consists of ferrochelatase, protoporphyrinogen oxidase and aminolevulinic acid synthase-2. Additional proteins involved in iron and intermediary metabolism as well as mitochondrial transporters were identified as potential partners in this complex. The data are consistent with the known location of protein components and support a model of transient protein-protein interactions within a dynamic protein complex.
Biomedical and Health Sciences Institute, University of Georgia, Athens, Georgia, United States of America; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America; GRU-UGA Medical Partnership, University of Georgia, Athens, Georgia, United States of America.
Amy E
AE
Medlock
Biomedical and Health Sciences Institute, University of Georgia, Athens, Georgia, United States of America; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America; GRU-UGA Medical Partnership, University of Georgia, Athens, Georgia, United States of America.
Mesafint T
MT
Shiferaw
Biomedical and Health Sciences Institute, University of Georgia, Athens, Georgia, United States of America; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America.
Jason R
JR
Marcero
Department of Biological Chemistry and the Institute of Genomics and Proteomics, University of California Los Angeles, Los Angeles, California, United States of America.
Ajay A
AA
Vashisht
Department of Biological Chemistry and the Institute of Genomics and Proteomics, University of California Los Angeles, Los Angeles, California, United States of America.
James A
JA
Wohlschlegel
Division of Hematology, Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah, United States of America.
John D
JD
Phillips
Biomedical and Health Sciences Institute, University of Georgia, Athens, Georgia, United States of America; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America; Department of Microbiology, University of Georgia, Athens, Georgia, United States of America.
Harry A
HA
Dailey
D000624:5-Aminolevulinate Synthetase / Q000378:metabolism; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000818:Animals; D045744:Cell Line, Tumor; D005294:Ferrochelatase / Q000378:metabolism; D006418:Heme / Q000096:biosynthesis / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism*; D011166:Porphyrins / Q000096:biosynthesis / Q000378:metabolism*; D050768:Protoporphyrinogen Oxidase / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; C410734:Abcb10 protein, mouse; D046912:Multiprotein Complexes; D011166:Porphyrins; D006418:Heme; D050768:Protoporphyrinogen Oxidase; D000624:5-Aminolevulinate Synthetase; D005294:Ferrochelatase