Sorek, N., Department of Plant Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
Poraty, L., Department of Plant Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
Sternberg, H., Department of Plant Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
Bar, E., Department of Field and Vegetable Crops, Agricultural Research Organization, Newe Ya'ar Reseach Center, P.O. Box 1021, Ramat Yishay 30095, Israel
Lewinsohn, E., Department of Field and Vegetable Crops, Agricultural Research Organization, Newe Ya'ar Reseach Center, P.O. Box 1021, Ramat Yishay 30095, Israel
Yalovsky, S., Department of Plant Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel

ROPs or RACs are plant Rho-related GTPases implicated in the regulation of a multitude of signaling pathways that function at the plasma membrane by virtue of posttranslational lipid modifications. The relationship between ROP activation status and membrane localization has not been established. Here we demonstrate that endogenous ROPs, as well as a transgenic His 6-green fluorescent protein (GFP)-AtROP6 fusion protein, were partitioned between Triton X-100-soluble and -insoluble membranes. In contrast, an activated His 6-GFP-Atrop6 CA mutant protein accumulated exclusively in detergent-resistant membranes. GDP induced accumulation of ROPs in Triton-soluble membranes, whereas GTPγS induced accumulation of ROPs in detergent-resistant membranes. Recombinant wild-type and constitutively active AtROP6 isoforms were purified from Arabidopsis plants, and their lipids were cleaved and analyzed by gas chromatography-coupled mass spectrometry. In Triton-soluble membranes, wild-type AtROP6 was only prenylated, primarily by geranylgeranyl. The activated AtROP6 that accumulated in detergent-resistant membranes was modified by prenyl and acyl lipids. The acyl lipids were identified as palmitic and stearic acids. In agreement, activated His 6-GFP-Atrop6 CAmS 156 in which cysteine 156 was mutated into serine accumulated in Triton-soluble membranes. These findings show that upon GTP binding and activation, AtROP6 and possibly other ROPs are transiently S acylated, which induces their partitioning into detergent-resistant membranes. Copyright © 2007, American Society for Microbiology. All Rights Reserved.

This article has been retracted:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1820497/