Expression of bacteriorhodopsin in Sf9 and COS-1 cells

Jürgen Heymann, Rama Jager, Sriram Subramaniam

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


We report studies on the expression of the archaebacterial membrane protein bacteriorhodopsin in Sf9 insect cells and in COS-1 mammalian cells. In both cell systems, the apoprotein bacterio-opsin was expressed at levels of ~1 μg/106 cells. Immunofluorescence studies showed that the expressed protein was accumulated in the endoplasmic reticulum. However, upon addition of all-trans retinal to membranes isolated from either Sf9 or COS-1 cells expressing bacterio-opsin, the characteristic bacteriorhodopsin chromophore (λ(max) at ~560 nm) was rapidly generated. This is in contrast to bacterio- opsin expressed in E. coli, which cannot be functionally reconstituted with retinal unless it is first denatured, and then renatured in vitro. These studies demonstrate that the bacterio-opsin expressed is correctly folded and show that localization of a heterologously expressed membrane protein in the endoplasmic reticulum does not necessarily imply that it is misfolded.

Original languageEnglish (US)
Pages (from-to)55-59
Number of pages5
JournalJournal of Bioenergetics and Biomembranes
Issue number1
StatePublished - 1997


  • folding
  • intracellular transport
  • Membrane protein
  • rhodopsin

ASJC Scopus subject areas

  • Physiology
  • Cell Biology


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