Skip to main content
ARS Home » Midwest Area » Urbana, Illinois » Global Change and Photosynthesis Research » Research » Publications at this Location » Publication #197850
Title: POSSIBLE LINK BETWEEN METHIONINE OXIDATION AND PROTEIN PHOSPHORYLATION

Author
item HARDIN, SHANE - UNIVERSITY OF ILLINIOS
item TIEN, MING - PA STATE UNIVERSITY
item Huber, Steven

Submitted to: American Society of Plant Biologists
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2006
Publication Date: 7/1/2006
Citation: Hardin, S., Tien, M., Huber, S.C. 2006. Possible link between methionine oxidation and protein phosphorylation [abstract]. American Society of Plant Biologists. Paper no. 07011. Available: http://abstracts.aspb.org/pb2006/public/P07/P07011.html.

Interpretive Summary:

Technical Abstract: Aerobic metabolism leads to the production of reactive oxygen species that may damage proteins. Methionine residues in proteins are particularly susceptible to oxidation to methionine sulfoxide (MetSO) converting its side chain from hydrophobic to hydrophilic. We postulated that this could have a significant impact on target protein phosphorylation. For example, calcium-dependent protein kinases (CDPKs) are known to target at least three distinct phosphorylation motifs that all require hydrophobic residues at critical positions relative to the acceptor Ser/Thr. Using synthetic peptides, we found that when Met residues are present at the critical positions, their oxidation inhibited phosphorylation by two distinct CDPKs. The presence of methionine sulfoxide at non-critical positions had no effect. In silico analysis predicts numerous proteins that may be dually regulated by both reversible phosphorylation and methionine oxidation. To examine this effect in vivo, we are studying transgenic Arabidopsis plants overexpressing a peptide-methionine sulfoxide reductase (cPMSRA3). Phosphoproteomic analysis of these plants using 1D- and 2D-PAGE with phosphospecific staining suggests that several proteins contain relatively higher levels of phosphorylation when methionine sulfoxide content is reduced, consistent with results using peptide substrates. Preliminary MALDI-ToF identifications suggest that lipoxygenase, two fructose-bisphosphate aldolase isoforms, and the light-repressible receptor protein kinase are specifically altered. The physiological significance of methionine oxidation of these phosphoproteins is being pursued.