title: Chorein Sensitive Dopamine Release from Pheochromocytoma (PC12) Cells.
abstract: BACKGROUND
  Chorein, a protein supporting activation of phosphoinositide 3 kinase (PI3K), participates in the regulation of actin polymerization and cell survival. A loss of function mutation of the chorein encoding gene VPS13A (vacuolar protein sorting-associated protein 13A) leads to chorea-acanthocytosis (ChAc), a neurodegenerative disorder with simultaneous erythrocyte akanthocytosis. In blood platelets chorein deficiency has been shown to compromise expression of vesicle-associated membrane protein 8 (VAMP8) and thus degranulation. The present study explored whether chorein is similarly involved in VAMP8 expression and dopamine release of pheochromocytoma (PC12) cells.
  
  
  METHODS
  Chorein was down-regulated by silencing in PC12 cells. Transmission electron microscopy was employed to quantify the number of vesicles, RT-PCR to determine transcript levels, Western blotting to quantify protein expression and ELISA to determine dopamine release.
  
  
  RESULTS
  Chorein silencing significantly reduced the number of vesicles, VAMP8 transcript levels and VAMP8 protein abundance. Increase of extracellular K+ from 5 mM to 40 mM resulted in marked stimulation of dopamine release, an effect significantly blunted by chorein silencing.
  
  
  CONCLUSIONS
  Chorein deficiency down-regulates VAMP8 expression, vesicle numbers and dopamine release in pheochromocytoma cells.
authors.affiliation: Department of Physiology, University of Tx00FC;bingen, Tx00FC;bingen, Germany.
authors.forename: Sabina
authors.initials: S
authors.lastname: Honisch
authors.forename: Birgit
authors.initials: B
authors.lastname: Fehrenbacher
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Lebedeva
authors.forename: Ioana
authors.initials: I
authors.lastname: Alesutan
authors.forename: Tatsiana
authors.initials: T
authors.lastname: Castor
authors.forename: Saad
authors.initials: S
authors.lastname: Alkahtani
authors.forename: Saud
authors.initials: S
authors.lastname: Alarifi
authors.forename: Martin
authors.initials: M
authors.lastname: Schaller
authors.forename: Christos
authors.initials: C
authors.lastname: Stournaras
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D046529:Microscopy, Electron, Transmission; D016716:PC12 Cells / Q000187:drug effects / Q000648:ultrastructure; D011189:Potassium Chloride / Q000494:pharmacology; D050683:R-SNARE Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D051381:Rats; D014162:Transfection; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D050683:R-SNARE Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C429654:VPS13A protein, human; C491830:Vamp8 protein, rat; D033921:Vesicular Transport Proteins; D011189:Potassium Chloride; D004298:Dopamine