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Association of Arabidopsis type‐II ROPs with the plasma membrane requires a conserved C‐terminal sequence motif and a proximal polybasic domain
Author(s) -
Lavy Meirav,
Yalovsky Shaul
Publication year - 2006
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2006.02749.x
Subject(s) - arabidopsis , prenylation , consensus sequence , biology , peptide sequence , wild type , conserved sequence , biochemistry , microbiology and biotechnology , chemistry , gene , mutant , enzyme
Summary Plant ROPs (or RACs) are soluble Ras‐related small GTPases that are attached to cell membranes by virtue of the post‐translational lipid modifications of prenylation and S‐acylation. ROPs (RACs) are subdivided into two major subgroups called type‐I and type‐II. Whereas type‐I ROPs terminate with a conserved CaaL box and undergo prenylation, type‐II ROPs undergo S‐acylation on two or three C‐terminal cysteines. In the present work we determined the sequence requirement for association of Arabidopsis type‐II ROPs with the plasma membrane. We identified a conserved sequence motif, designated the GC‐CG box, in which the modified cysteines are flanked by glycines. The GC‐CG box cysteines are separated by five to six mostly non‐polar residues. Deletion of this sequence or the introduction of mutations that change its nature disrupted the association of ROPs with the membrane. Mutations that changed the GC‐CG box glycines to alanines also interfered with membrane association. Deletion of a polybasic domain proximal to the GC‐CG box disrupted the plasma membrane association of AtROP10. A green fluorescent protein fusion protein containing the C‐terminal 25 residues of AtROP10, including its polybasic domain and GC‐CG box, was primarily associated with the plasma membrane but a similar fusion protein lacking the polybasic domain was exclusively localized in the soluble fraction. These data provide evidence for the minimal sequence required for plasma membrane association of type‐II ROPs in Arabidopsis and other plant species.