Essential Role of the G-Domain in Targeting of the Protein Import Receptor atToc159 to the Chloroplast Outer Membrane

Authors

Jörg Bauer, BASF Plant Science GmbH
Andreas Hiltbrunner, Institute of Plant Sciences
Petra Weibel, Institute of Plant Sciences
Pierre-Alexandre Vidi, Institute of Plant Sciences
Mayte Alvarez-Huerta, Institute of Plant Sciences
Matthew D. Smith, Wilfrid Laurier UniversityFollow
Danny J. Schnell, University of Massachusetts
Felix Kessler, Institute of Plant Sciences

Document Type

Article

Publication Date

2002

Department

Biology

Abstract

Two homologous GTP-bindin proteins, atToc33 and atToc159, control access of cytosolic precursor proteins to the chloroplast, at Toc33 is a constitutive outer chloroplast membrane protein, whereas the precusor receptor atToc159 may be able to switch between a soluble and an integral membrane form. By transient expression of GFP fusion proteins, mutant analysis, and biochemical experimentation, we demonstrate that the GTP-binding domain regulates the targeting of cytosolic atToc159 to the chloroplast and mediates the switch between cytosolic and integral membrane forms. Mutant atToc159, unable to bind GTP, does not reinstate a green phenotype in an albino mutant (ppi2) lacking endogenous atToc159, remaining trapped in the cytosol. Thus, the function of atToc159 in chloroplast biogenesis is dependent on an intrinsic GTP-regulated swtich that controls localization of the receptor to the chloroplast envelope.

Comments

This article was originally published in Journal of Cell Biology, 159(5): 845-854. © 2002 Rockefeller University Press

Recommended Citation

Bauer, Jörg; Hiltbrunner, Andreas; Weibel, Petra; Vidi, Pierre-Alexandre; Alvarez-Huerta, Mayte; Smith, Matthew D.; Schnell, Danny J.; and Kessler, Felix, "Essential Role of the G-Domain in Targeting of the Protein Import Receptor atToc159 to the Chloroplast Outer Membrane" (2002). Biology Faculty Publications. 48.
https://scholars.wlu.ca/biol_faculty/48