Erythropoietin signaling regulates heme biosynthesis
Abstract
Heme is required for survival of all cells, and in most eukaryotes, is produced through a series of eight enzymatic reactions. Although heme production is critical for many cellular processes, how it is coupled to cellular differentiation is unknown. Here, using zebrafish, murine, and human models, we show that erythropoietin (EPO) signaling, together with the GATA1 transcriptional target, AKAP10, regulates heme biosynthesis during erythropoiesis at the outer mitochondrial membrane. This integrated pathway culminates with the direct phosphorylation of the crucial heme biosynthetic enzyme, ferrochelatase (FECH) by protein kinase A (PKA). Biochemical, pharmacological, and genetic inhibition of this signaling pathway result in a block in hemoglobin production and concomitant intracellular accumulation of protoporphyrin intermediates. Broadly, our results implicate aberrant PKA signaling in the pathogenesis of hematologic diseases. We propose a unifying model in which the erythroid transcriptional program works in concert with post-translational mechanisms to regulate heme metabolism during normal development.
Article and author information
Author details
Funding
National Heart, Lung, and Blood Institute (P01 HL032262)
- Barry H Paw
National Institute of Diabetes and Digestive and Kidney Diseases (R01 DK096501)
- Harry A Dailey
American Society of Hematology
- Daniel E Bauer
National Heart, Lung, and Blood Institute (P01 HL032262)
- Harvey F Lodish
- Daniel E Bauer
- Stuart H Orkin
- Alan B Cantor
National Institutes of Health (R01 GM115591)
- David J Pagliarini
National Institute of Diabetes and Digestive and Kidney Diseases (R01 DK098672)
- David J Pagliarini
National Institutes of Health (P41 GM108538)
- Joshua J Coon
National Institute of Diabetes and Digestive and Kidney Diseases (U54 DK110858)
- John D Phillips
Diamond Blackfan Anemia Foundation
- Barry H Paw
National Institute of Diabetes and Digestive and Kidney Diseases (R01 DK070838)
- Barry H Paw
American Cancer Society (RSG-13-379-01-LIB)
- Takahiro Maeda
American Society of Hematology
- Jacky Chung
Canadian Institutes of Health Research
- Jacky Chung
National Institute of Diabetes and Digestive and Kidney Diseases (K08 DK093705)
- Daniel E Bauer
National Institute of Diabetes and Digestive and Kidney Diseases (R01 DK052380)
- Jerry Kaplan
National Institute of Diabetes and Digestive and Kidney Diseases (R01 DK090257)
- John D Phillips
National Institutes of Health (R01 GM114122)
- Joshua J Coon
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- David Ginsburg, Howard Hughes Medical Institute, University of Michigan, United States
Ethics
Animal experimentation: In full compliance with BWH IACUC A4752-01 (Protocol #2016N000117) and BCH IACUC Protocol #15-07-2974R.
Version history
- Received: December 30, 2016
- Accepted: May 28, 2017
- Accepted Manuscript published: May 29, 2017 (version 1)
- Version of Record published: June 20, 2017 (version 2)
Copyright
© 2017, Chung et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 2,454
- views
-
- 515
- downloads
-
- 34
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Further reading
-
- Computational and Systems Biology
- Developmental Biology
The gain-of-function mutation in the TALK-1 K+ channel (p.L114P) is associated with maturity-onset diabetes of the young (MODY). TALK-1 is a key regulator of β-cell electrical activity and glucose-stimulated insulin secretion. The KCNK16 gene encoding TALK-1 is the most abundant and β-cell-restricted K+ channel transcript. To investigate the impact of KCNK16 L114P on glucose homeostasis and confirm its association with MODY, a mouse model containing the Kcnk16 L114P mutation was generated. Heterozygous and homozygous Kcnk16 L114P mice exhibit increased neonatal lethality in the C57BL/6J and the CD-1 (ICR) genetic background, respectively. Lethality is likely a result of severe hyperglycemia observed in the homozygous Kcnk16 L114P neonates due to lack of glucose-stimulated insulin secretion and can be reduced with insulin treatment. Kcnk16 L114P increased whole-cell β-cell K+ currents resulting in blunted glucose-stimulated Ca2+ entry and loss of glucose-induced Ca2+ oscillations. Thus, adult Kcnk16 L114P mice have reduced glucose-stimulated insulin secretion and plasma insulin levels, which significantly impairs glucose homeostasis. Taken together, this study shows that the MODY-associated Kcnk16 L114P mutation disrupts glucose homeostasis in adult mice resembling a MODY phenotype and causes neonatal lethality by inhibiting islet insulin secretion during development. These data suggest that TALK-1 is an islet-restricted target for the treatment for diabetes.
-
- Developmental Biology
- Structural Biology and Molecular Biophysics
A crucial event in sexual reproduction is when haploid sperm and egg fuse to form a new diploid organism at fertilization. In mammals, direct interaction between egg JUNO and sperm IZUMO1 mediates gamete membrane adhesion, yet their role in fusion remains enigmatic. We used AlphaFold to predict the structure of other extracellular proteins essential for fertilization to determine if they could form a complex that may mediate fusion. We first identified TMEM81, whose gene is expressed by mouse and human spermatids, as a protein having structural homologies with both IZUMO1 and another sperm molecule essential for gamete fusion, SPACA6. Using a set of proteins known to be important for fertilization and TMEM81, we then systematically searched for predicted binary interactions using an unguided approach and identified a pentameric complex involving sperm IZUMO1, SPACA6, TMEM81 and egg JUNO, CD9. This complex is structurally consistent with both the expected topology on opposing gamete membranes and the location of predicted N-glycans not modeled by AlphaFold-Multimer, suggesting that its components could organize into a synapse-like assembly at the point of fusion. Finally, the structural modeling approach described here could be more generally useful to gain insights into transient protein complexes difficult to detect experimentally.