title: Towards the development of Bacillus subtilis as a cell factory for membrane proteins and protein complexes.
abstract: BACKGROUND
  The Gram-positive bacterium Bacillus subtilis is an important producer of high quality industrial enzymes and a few eukaryotic proteins. Most of these proteins are secreted into the growth medium, but successful examples of cytoplasmic protein production are also known. Therefore, one may anticipate that the high protein production potential of B. subtilis can be exploited for protein complexes and membrane proteins to facilitate their functional and structural analysis. The high quality of proteins produced with B. subtilis results from the action of cellular quality control systems that efficiently remove misfolded or incompletely synthesized proteins. Paradoxically, cellular quality control systems also represent bottlenecks for the production of various heterologous proteins at significant concentrations.
  
  
  CONCLUSIONS
  While inactivation of quality control systems has the potential to improve protein production yields, this could be achieved at the expense of product quality. Mechanisms underlying degradation of secretory proteins are nowadays well understood and often controllable. It will therefore be a major challenge for future research to identify and modulate quality control systems of B. subtilis that limit the production of high quality protein complexes and membrane proteins, and to enhance those systems that facilitate assembly of these proteins.
authors.affiliation: Department of Medical Microbiology, University Medical Center Groningen and University of Groningen, Hanzeplein 1, P,O, Box 30001, 9700 RB Groningen, The Netherlands. J.M.van.Dijl@med.umcg.nl.
authors.forename: Jessica C
authors.initials: JC
authors.lastname: Zweers
authors.forename: Imrich
authors.initials: I
authors.lastname: Barák
authors.forename: Dörte
authors.initials: D
authors.lastname: Becher
authors.forename: Arnold Jm
authors.initials: AJ
authors.lastname: Driessen
authors.forename: Michael
authors.initials: M
authors.lastname: Hecker
authors.forename: Vesa P
authors.initials: VP
authors.lastname: Kontinen
authors.forename: Manfred J
authors.initials: MJ
authors.lastname: Saller
authors.forename: L'udmila
authors.initials: L
authors.lastname: Vavrová
authors.forename: Jan Maarten
authors.initials: JM
authors.lastname: van Dijl