Cover Picture: Proteomics 18'09

Abstract

AbstractDo rafts jump ship?A raft, as most of us picture it, is a collection of floating material tied together to keep some kind of load afloat. A domain, on the other hand, is the area ruled by an individual, often based on inheritance. The cholesterol‐rich plasma membrane patches found on cell surfaces seem to fit the description of a domain reasonably well ‐ floating on the cell surface, they participate in cell signaling and endocytosis. And, presumably, when the host cell divides, its progeny receive a startup supply of domains (by foul means or fair). Kim et al. explored this question of distribution using synthetic glycosphingolipids (C8De and C8Lt). C8De stimulates endocytosis and rearrangement of domain proteins. Using lipid‐free methods, domains were isolated and analyzed by 2DGE, MALDI‐TOFMS and immunofluorescent microscopy. Proteins transferred to the surface after treatment were involved in ubiquitination, lipid transfer, integrin, small GTPases and several unknown functions.Kim, S.‐Y. et al., Proteomics 2009, 9, 4321–4328.Fresh frozen versus formalin fixed ‐ and the winner is……biomedical research. The existence of a reservoir of millions of samples, many paired or containing areas of both normal and affected cells, has attracted many proteome researchers. These formalin‐fixed paraffin embedded (FFPE) samples, however, have proven very difficult to exploit. Addis et al, report here a protocol that yields full‐length protein products, suitable for 2D PAGE, Western (immuno) blots, LC‐MS/MS and MALDI‐MS, from FFPE sections. Protein extractions were performed using detergents and reducing agents and followed by TCA/acetone precipitation to remove interfering material. As many as 250 spots could be identified from FFPE sheep skeletal muscle, whereas 390 were found in fresh frozen samples. Not all 2D spots matched perfectly, but patterns were very reproducible and easily matched.Addis, M. et al., Proteomics 2009, 9, 4329–4339.Peas porridge hot, peas porridge cold…Agricultural applications of genetic engineering usually have regulatory requirements that GM offspring be essentially equivalent to the parental line with the exception of the target gene. This can be hard to do or hard to prove. Take the case of field peas, Mendel's favorite. To give the crop resistance to pea weevil, the α‐amylase inhibitor (α‐AI1) of the common bean was inserted into peas. Unfortunately, the engineers got more than they bargained for: the GM peas caused undesirable immunological effects in feeding tests. Upon proteomic analysis, Chen, et al., found a problem ‐ transfected genetic material included 33 genes that were over‐ or under‐expressed in five different patterns. Most of the problems were associated with Agrobacterium‐mediated events. Of the 16 proteins identified by 2D GE and MALDI‐TOF/TOF MS, many were potentially allergenic food storage proteins. A 2D gel is a cheap way to check the temperature of the soup.Chen, H. et al., Proteomics 2009, 9, 4406–4415.