title: Neuregulin-activated ERBB4 induces the SREBP-2 cholesterol biosynthetic pathway and increases low-density lipoprotein uptake.
abstract: Cholesterol is a lipid that is critical for steroid hormone production and the integrity of cellular membranes, and, as such, it is essential for cell growth. The epidermal growth factor receptor (EGFR) family member ERBB4, which forms signaling complexes with other EGFR family members, can undergo ligand-induced proteolytic cleavage to release a soluble intracellular domain (ICD) that enters the nucleus to modify transcription. We found that ERBB4 activates sterol regulatory element binding protein-2 (SREBP-2) to enhance low-density lipoprotein (LDL) uptake and cholesterol biosynthesis. Expression of the ERBB4 ICD in mammary epithelial cells or activation of ERBB4 with the ligand neuregulin 1 (NRG1) induced the expression of SREBP target genes involved in cholesterol biosynthesis, including HMGCR and HMGCS1, and lipid uptake, LDLR, which encodes the LDL receptor. Addition of NRG1 increased the abundance of the cleaved, mature form of SREBP-2 through a pathway that was blocked by addition of inhibitors of PI3K (phosphatidylinositol 3-kinase) or dual inhibition of mammalian target of rapamycin complex 1 (mTORC1) and mTORC2, but not by inhibition of AKT or mTORC1. Pharmacological inhibition of the activity of SREBP site 1 protease or of all EGFR family members (with lapatinib), but not EGFR alone (with erlotinib), impaired NRG1-induced expression of cholesterol biosynthesis genes. Collectively, our findings indicated that activation of ERBB4 promotes SREBP-2-regulated cholesterol metabolism. The connections of EGFR and ERBB4 signaling with SREBP-2-regulated cholesterol metabolism are likely to be important in ERBB-regulated developmental processes and may contribute to metabolic remodeling in ERBB-driven cancers.
authors.affiliation: Department of Pathology and Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06510, USA.
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Haskins
authors.affiliation: Department of Pathology and Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06510, USA.
authors.forename: Shannon
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Pathology and Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06510, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Means
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Joanne K
authors.initials: JK
authors.lastname: Kelleher
authors.affiliation: Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510, USA.
authors.forename: Gary W
authors.initials: GW
authors.lastname: Cline
authors.affiliation: Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06510, USA.
authors.forename: Alberto
authors.initials: A
authors.lastname: Canfrán-Duque
authors.affiliation: Department of Pathology and Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06510, USA. Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06510, USA.
authors.forename: Yajaira
authors.initials: Y
authors.lastname: Suárez
authors.affiliation: Department of Pathology and Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06510, USA. df.stern@yale.edu.
authors.forename: David F
authors.initials: DF
authors.lastname: Stern
mesh_terms: D045744:Cell Line, Tumor; D002784:Cholesterol / Q000096:biosynthesis* / Q000235:genetics; D005260:Female; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000235:genetics / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000235:genetics / Q000378:metabolism*; D000076222:Mechanistic Target of Rapamycin Complex 1; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D020890:Neuregulin-1 / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D066247:Receptor, ErbB-4 / Q000235:genetics / Q000378:metabolism*; D011973:Receptors, LDL / Q000235:genetics / Q000378:metabolism*; D051782:Sterol Regulatory Element Binding Protein 2 / Q000235:genetics / Q000378:metabolism*; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: C573412:LDLR protein, human; D008077:Lipoproteins, LDL; D046912:Multiprotein Complexes; C094131:NRG1 protein, human; D020890:Neuregulin-1; D011973:Receptors, LDL; C497390:SREBF2 protein, human; D051782:Sterol Regulatory Element Binding Protein 2; D002784:Cholesterol; C553220:HMGCR protein, human; D006903:Hydroxymethylglutaryl CoA Reductases; C587689:ERBB4 protein, human; D066247:Receptor, ErbB-4; D000076222:Mechanistic Target of Rapamycin Complex 1; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases