title: The mTORC1/4E-BP pathway coordinates hemoglobin production with L-leucine availability.
abstract: In multicellular organisms, the mechanisms by which diverse cell types acquire distinct amino acids and how cellular function adapts to their availability are fundamental questions in biology. We found that increased neutral essential amino acid (NEAA) uptake was a critical component of erythropoiesis. As red blood cells matured, expression of the amino acid transporter gene Lat3 increased, which increased NEAA import. Inadequate NEAA uptake by pharmacologic inhibition or RNAi-mediated knockdown of LAT3 triggered a specific reduction in hemoglobin production in zebrafish embryos and murine erythroid cells through the mTORC1 (mammalian target of rapamycin complex 1)/4E-BP (eukaryotic translation initiation factor 4E-binding protein) pathway. CRISPR-mediated deletion of members of the 4E-BP family in murine erythroid cells rendered them resistant to mTORC1 and LAT3 inhibition and restored hemoglobin production. These results identify a developmental role for LAT3 in red blood cells and demonstrate that mTORC1 serves as a homeostatic sensor that couples hemoglobin production at the translational level to sufficient uptake of NEAAs, particularly L-leucine.
authors: Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors: Jacky
authors: J
authors: Chung
authors: Division of Hematology-Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA. Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
authors: Daniel E
authors: DE
authors: Bauer
authors: Division of Hematology-Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA. Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
authors: Alireza
authors: A
authors: Ghamari
authors: Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors: Christopher P
authors: CP
authors: Nizzi
authors: Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors: Kathryn M
authors: KM
authors: Deck
authors: Department of Pediatrics, Center for Pediatric Biomedical Research, University of Rochester Medical Center, Rochester, NY 14642, USA.
authors: Paul D
authors: PD
authors: Kingsley
authors: Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors: Yvette Y
authors: YY
authors: Yien
authors: Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors: Nicholas C
authors: NC
authors: Huston
authors: Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors: Caiyong
authors: C
authors: Chen
authors: Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors: Iman J
authors: IJ
authors: Schultz
authors: Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors: Arthur J
authors: AJ
authors: Dalton
authors: Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors: Johannes G
authors: JG
authors: Wittig
authors: Department of Pediatrics, Center for Pediatric Biomedical Research, University of Rochester Medical Center, Rochester, NY 14642, USA.
authors: James
authors: J
authors: Palis
authors: Division of Hematology-Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA. Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
authors: Stuart H
authors: SH
authors: Orkin
authors: Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
authors: Harvey F
authors: HF
authors: Lodish
authors: Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors: Richard S
authors: RS
authors: Eisenstein
authors: Division of Hematology-Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA. Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
authors: Alan B
authors: AB
authors: Cantor
authors: Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. Division of Hematology-Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA. Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA. bpaw@rics.bwh.harvard.edu.
authors: Barry H
authors: BH
authors: Paw
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D026923:Amino Acid Transport Systems, Basic / Q000235:genetics / Q000378:metabolism; D000818:Animals; D030801:Animals, Genetically Modified; D064113:CRISPR-Cas Systems; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000098:blood supply / Q000196:embryology / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000378:metabolism; D041905:Erythroid Cells / Q000378:metabolism; D004920:Erythropoiesis / Q000235:genetics; D039642:Eukaryotic Initiation Factors / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D057809:HEK293 Cells; D006454:Hemoglobins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007930:Leucine / Q000378:metabolism*; D000076222:Mechanistic Target of Rapamycin Complex 1; D051379:Mice; D018613:Microscopy, Confocal; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D015027:Zebrafish
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D026923:Amino Acid Transport Systems, Basic; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C499527:Eif4ebp1 protein, mouse; C491255:Eif4ebp2 protein, mouse; D039642:Eukaryotic Initiation Factors; D006454:Hemoglobins; C542311:LAT3 protein, mouse; D046912:Multiprotein Complexes; D010750:Phosphoproteins; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases; D007930:Leucine