|Oh, Man Ho|
Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2011
Publication Date: 4/1/2011
Publication URL: http://naldc.nal.usda.gov/catalog/49431
Citation: Wu, X., Oh, M., Schwarz, E., Larue, C., Sivaguru, M., Imai, B.S., Yau, P.M., Ort, D.R., Huber, S.C. 2011. Lysine acetylation is a widespread protein modification for diverse proteins in Arabidopsis. Plant Physiology. 155:1769-1778. Interpretive Summary: Lysine acetylation is a post-translational modification to a protein that involves addition of an acetyl group to the amine-N of the lysine side chain. This modification has long been known to occur on histone proteins that are associated with DNA in the nucleus, and has been considered to be a histone-specific modification. Addition of the acetyl group is significant, because it removes the positive charge of the lysine side chain and thus can profoundly impact the activity, stability, and localization of a protein. We now report that this modification occurs on numerous non-histone proteins outside of the nucleus in plant cells. Preliminary results are presented that acetylation may play a role in regulating the light harvesting capability of plant chloroplast membranes, and also the regulation of an important protein that controls the process of protein synthesis, known as translation, in plants. These results provide a cornerstone for future work to investigate this important posttranslational modification in plants and elucidate its full impact on metabolism and cellular function.
Technical Abstract: Lysine acetylation (LysAc), a form of reversible protein post translational modification previously known only for histone proteins in plants, is shown to be wide spread in Arabidopsis. Sixty five lysine modification sites were identified on 58 proteins, which operate in a wide variety of pathways/processes and are located in various cellular compartments. A number of photosynthesis-related proteins are among this group of LysAc proteins, including photosystem II (PSII) subunits, light-harvesting chlorophyll a/b-binding proteins (LHCb), ribulose-bisphosphate carboxylase/oxygenase (Rubisco) large and small subunits, and chloroplastic ATP synthase (ß subunit). Using 2-dimensional native green/SDS gels, the mobile pool of LHCb was separated from the pool tightly bound to PSII and shown to have substantially higher level of LysAc, implying that LysAc may play a role in the formation of LHCb complexes. Several potential LysAc sites were identified on eukaryotic elongation factor 1A (eEF-1A) by LC/MS and using sequence- and modification-specific antibodies the acetylation of Lys-227 and Lys-306 was established. Lys-306 is contained within a predicted calmodulin (CaM)-binding sequence and acetylation of Lys-306 strongly inhibited the interactions of eEF-1A synthetic peptides with CaM recombinant proteins in vitro. These results suggest that LysAc of eEF-1A may directly affect regulatory properties and localization of the protein within the cell. Overall, these findings reveal the possibility that reversal LysAc may be an important and previously unknown regulatory function of a large number of non-histone proteins affecting a wide range of pathways and processes in Arabidopsis and likely in all plants.