title: The tumor suppressor RhoBTB1 controls Golgi integrity and breast cancer cell invasion through METTL7B.
abstract: RhoBTB1 and 2 are atypical members of the Rho GTPase family of signaling proteins. Unlike other Rho GTPases, RhoBTB1 and 2 undergo silencing or mutation in a wide range of epithelial cancers; however, little is known about the consequences of this loss of function.
  
  
  
  We analyzed transcriptome data to identify transcriptional targets of RhoBTB2. We verified these using Q-PCR and then used gene silencing and cell imaging to determine the cellular function of these targets downstream of RhoBTB signaling.
  
  
  
  RhoBTB1 and 2 regulate the expression of the methyltransferases METTL7B and METTL7A, respectively. RhoBTB1 regulates the integrity of the Golgi complex through METTL7B. RhoBTB1 is required for expression of METTL7B and silencing of either protein leads to fragmentation of the Golgi. Loss of RhoBTB1 expression is linked to Golgi fragmentation in breast cancer cells. Restoration of normal RhoBTB1 expression rescues Golgi morphology and dramatically inhibits breast cancer cell invasion.
  
  
  
  Loss of RhoBTB1 expression in breast cancer cells leads to Golgi fragmentation and hence loss of normal polarity.
authors.affiliation: School of Biochemistry, Biomedical Sciences Building, University Walk, University of Bristol, Bristol, UK.
authors.forename: Caroline M
authors.initials: CM
authors.lastname: McKinnon
authors.affiliation: School of Biochemistry, Biomedical Sciences Building, University Walk, University of Bristol, Bristol, UK. h.mellor@bristol.ac.uk.
authors.forename: Harry
authors.identifier: 0000-0003-3894-0623
authors.initials: H
authors.lastname: Mellor
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002352:Carrier Proteins; D002460:Cell Line; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D009361:Neoplasm Invasiveness; D015398:Signal Transduction; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D020741:rho GTP-Binding Proteins
chemical_list: D002352:Carrier Proteins; C000626366:METTL7B protein, human; C000626367:RhoBTB1 protein, human; D025521:Tumor Suppressor Proteins; D020741:rho GTP-Binding Proteins
keywords: BTB domain; Cell invasion; Cell migration; Golgi fragmentation; Methyltransferase; Rho GTPases; RhoBTB1