IDENTIFICATION OF THE MAJOR LEAF PROTEINS SUBJECT TO O-GLCNAC POSSTRANSLATIONAL MODIFICATION.

Authors: QIU, QUANSHENG - UNIVERSITY OF ILLINOIS; HUBER, JOAN - UNIVERSITY OF ILLINOIS; Huber, Steven

Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/28/2005
Publication Date: 4/1/2005
Citation: Qiu, Q., Huber, J.L., Huber, S.C. 2005. Identification of the major leaf proteins subject to o-glcnac posstranslational modification [abstract]. Plant Biology Annual Meeting. Available: http://abstracts.aspb.org/pb2005/public/P69/7476.html.

Interpretive Summary:

Technical Abstract: Studies of protein oxidation during development and in response to stress typically measure DNPH-reactive carbonyl content. Numerous leaf proteins are found to contain DNPH-reactive carbonyls during normal growth and even growth in continuous darkness (etiolated maize seedlings). One reversible PTM that would also be detected with DNPH is the modication with O-linked N-acetylglucosamine (O-GlcNAc), which is known to be an abundant and dynamic modification in animals. Hence, it is important to determine to what extent O-GlcNAc occurs in plants. In the present study, we have done this using monoclonal antibodies (CTD 110.6) that are specific for the -O-GlcNAc modification. Leaves of Arabidopsis and soybean contain two major O-GlcNAc-containing proteins: Rubisco LSU and Lhcll. Both proteins were identified by immunoblotting, and interestingly, both are chloroplast proteins whereas the two known O-GlcNAC transferases are cytosolic/nuclear. Several distinct forms of Rubisco and Lhcll were resolved by 2-DE analysis. A subset of the Lhcll proteins appeared to be glycosylated. The Lhcll protein was also identified as a major leaf phosphoprotein.