Related Experiment Video
Updated: Jul 17, 2026

Studying Protein Import into Chloroplasts Using Protoplasts
Published on: December 10, 2018
Chloroplast biogenesis: the use of mutants to study the etioplast-chloroplast transition
Katrin Philippar1, Tina Geis, Iryna Ilkavets
1Department Biology I, Botany, Ludwig-Maximilians-University of Munich, Menzingerstrasse 67, D-80638 Munich, Germany.
Abstract:
In angiosperm plants, the etioplast-chloroplast transition is light-dependent. A key factor in this process is the protochlorophyllide oxidoreductase A (PORA), which catalyzes the light-induced reduction of protochlorophyllide to chlorophyllide. The import pathway of the precursor protein prePORA into chloroplasts was analyzed in vivo and in vitro by using homozygous loss-of-function mutants in genes coding for chlorophyllide a oxygenase (CAO) or for members of the outer-envelope solute-channel protein family of 16 kDa (OEP16), both of which have been implied to be key factors for the import of prePORA. Our in vivo analyses show that cao or oep16 mutants contain a normally structured prolamellar body that contains the protochlorophyllide holochrome. Furthermore, etioplasts from cao and oep16 mutants contain PORA protein as found by mass spectrometry. Our data demonstrate that both CAO and OEP16 are dispensable for chloroplast biogenesis and play no central role in the import of prePORA in vivo and in vitro as further indicated by protein import studies.
More Related Videos
Related Concept Videos
The Anatomy of Chloroplasts
Structure of Chloroplasts
A...
Export of Mitochondrial and Chloroplast Genes
Protein Transport to the Inner Chloroplast Membrane
Anatomy of Chloroplasts
Protein Transport to the Stroma
Protein complexes called the translocon of the outer chloroplast membrane or TOC complex, and the translocon of the inner chloroplast membrane or TIC complex mediate the...
Protein Transport to the Outer Chloroplast Membrane
Two models describe the mechanism of precursor recognition and entry across the outer membrane through the TOC complex. Model 1 suggests the newly synthesized precursor binds to the TOC receptor 159 and forms a complex.

