Cover Picture: Proteomics 12/2008

In this issue of Proteomics you will find the following highlighted articles: TAP tag! You're it! TAP tag is a considerably more sophisticated game than the one we played as kids. For one, the tag is something actual as opposed to that ethereal “it” which was attached to your being by unknown forces only extant during recess period. In this technical note, Kito et al. describe a clever way of using the Tandem Affinity Purification protocol coupled to stable mass isotope labeling to study the character of the association of molecules in complexes. By mixing a TAP + /mass isotope + tagged molecule with untagged molecules before or after affinity purification, they could distinguish stable associations from transient association from spurious noise. With some additional improvements, they should be able to generate quantitative interaction information such as the off and on rates of individual components. Kito, K. et al., Proteomics 2008, 8 , 2366–2370. Rafting into place: Malaria moves machinery of infection About two million people die each year of malaria. The disease is mosquito‐borne, caused by Plasmodium falciparum in humans, P. berghei in rodents. During the mammalian phase of its life cycle, the microbe multiplies in enucleated erythrocytes, regular red blood cells (RBC). The RBC is modified extensively for Plasmodium replication. Di Girolamo et al. here report their exploration of the role of “rafts” of detergent‐resistant membranes in sorting and positioning proteins essential to malarial replication. They applied proteomic techniques to membrane fractions and found rafts carried both malarial and host components. Plasmodial raft proteins were up‐ or down‐regulated by P. berghei genes at specific stages of the plasmodial life cycle. However, there also appear to be host factors that are used to internalize selected parasite products. The raft association seems to be quite dynamic for the erythrocyte phase, particularly with multifunctional protein 14–3‐3, known for regulating protein localization. Di Girolamo, F. et al., Proteomics 2008, 8 , 2500–2513. A multi‐dimensional proteomic analysis of ischemia‐reperfusion injury Cardiac surgery could be said to have a temporary mortality rate (ischemic arrest) of ∼100%, but the operative rate is generally <10%. A third metric is survival – roughly 24% of high‐risk patients will die within 3 years after surgery. The problem is due primarily to the effects of reperfusion at the conclusion of the surgery. Fert‐Bober et al. report here on the proteomes of rat heart proteins at various times post‐surgery, with or without reperfusion. Hearts were subjected to 0, 15, 20–25 and 30 min of post ischemia perfusion then tested for gelatinase and for mechanical function before selecting those destined for proteome determination. Samples were analyzed by 2‐DE, MALDI/TOF‐MS, and Coomassie staining. The findings were striking: most spots showed increased intensity if the hearts had not been reperfused and the converse if they had. Both sets of 2‐DE spots included metabolism enzymes, muscle components, anti‐oxidant and stress proteins. Fert‐Bober, J. et al., Proteomics 2008, 8 , 2543–2555.