scholarly journals Currents: Automated 2DE | Proteomics screen reveals in vivo kinase targets | Identifying lipid-protein interactions | Studying protein domains to discover binding specificities | Human liver proteome analysis | Fast microarray analysis with automated image detection | TOOLbox: Simulated shotgun experiments | BioText for searching figure captions | Hardklör for high-resolution MS/MS | Data dissemination with PrestOMIC

2007 ◽  
Vol 6 (9) ◽  
pp. 3363-3365
Keyword(s):  
High Resolution ◽  
Microarray Analysis ◽  
Protein Interactions ◽  
Human Liver ◽  
Data Dissemination ◽  
Proteome Analysis ◽  
Image Detection ◽  
Liver Proteome ◽  
Lipid Protein Interactions

The Origin of the Eukaryotic Cell Based on Conservation of Existing Interfaces

2006 ◽  
Vol 12 (4) ◽  
pp. 513-523 ◽  
Author(s):  
Albert D. G. de Roos
Keyword(s):  
Plasma Membrane ◽  
Protein Interactions ◽  
Self Assembly ◽  
Evolutionary Model ◽  
Lipid Vesicles ◽  
Eukaryotic Cell ◽  
The Self ◽  
Lipid Protein Interactions

Current theories about the origin of the eukaryotic cell all assume that during evolution a prokaryotic cell acquired a nucleus. Here, it is shown that a scenario in which the nucleus acquired a plasma membrane is inherently less complex because existing interfaces remain intact during evolution. Using this scenario, the evolution to the first eukaryotic cell can be modeled in three steps, based on the self-assembly of cellular membranes by lipid-protein interactions. First, the inclusion of chromosomes in a nuclear membrane is mediated by interactions between laminar proteins and lipid vesicles. Second, the formation of a primitive endoplasmic reticulum, or exomembrane, is induced by the expression of intrinsic membrane proteins. Third, a plasma membrane is formed by fusion of exomembrane vesicles on the cytoskeletal protein scaffold. All three self-assembly processes occur both in vivo and in vitro. This new model provides a gradual Darwinistic evolutionary model of the origins of the eukaryotic cell and suggests an inherent ability of an ancestral, primitive genome to induce its own inclusion in a membrane.

scholarly journals Toward a high resolution 2-DE profile of the normal human liver proteome using ultra-zoom gels

2011 ◽  
Vol 54 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Wei Mi ◽  
Xin Liu ◽  
Wei Jia ◽  
Lei Li ◽  
Yun Cai ◽  
...  
Keyword(s):  
High Resolution ◽  
Human Liver ◽  
Normal Human Liver ◽  
Liver Proteome ◽  
Normal Human

Effects of phosphatidylethanolamine glycation on lipid–protein interactions and membrane protein thermal stability

2008 ◽  
Vol 416 (1) ◽  
pp. 145-152 ◽  
Author(s):  
Valeria Levi ◽  
Ana M. Villamil Giraldo ◽  
Pablo R. Castello ◽  
Juan P. F. C. Rossi ◽  
F. Luis González Flecha
Keyword(s):  
Membrane Proteins ◽  
Protein Interactions ◽  
Membrane Lipids ◽  
Structural Rearrangement ◽  
Normal Functioning ◽  
Complex Organization ◽  
Lipid Glycation ◽  
Lipid Protein Interactions ◽  
The Stability

Non-enzymatic glycation of biomolecules has been implicated in the pathophysiology of aging and diabetes. Among the potential targets for glycation are biological membranes, characterized by a complex organization of lipids and proteins interacting and forming domains of different size and stability. In the present study, we analyse the effects of glycation on the interactions between membrane proteins and lipids. The phospholipid affinity for the transmembrane surface of the PMCA (plasma-membrane Ca2+-ATPase) was determined after incubating the protein or the phospholipids with glucose. Results show that the affinity between PMCA and the surrounding phospholipids decreases significantly after phosphospholipid glycation, but remains unmodified after glycation of the protein. Furthermore, phosphatidylethanolamine glycation decreases by ∼30% the stability of PMCA against thermal denaturation, suggesting that glycated aminophospholipids induce a structural rearrangement in the protein that makes it more sensitive to thermal unfolding. We also verified that lipid glycation decreases the affinity of lipids for two other membrane proteins, suggesting that this effect might be common to membrane proteins. Extending these results to the in vivo situation, we can hypothesize that, under hyperglycaemic conditions, glycation of membrane lipids may cause a significant change in the structure and stability of membrane proteins, which may affect the normal functioning of membranes and therefore of cells.

Phospholipid-Protein Interactions in the Formation of Prothrombin Activator

1965 ◽  
Vol 14 (03/04) ◽  
pp. 431-444 ◽  
Author(s):  
E. R Cole ◽  
J. L Koppel ◽  
J. H Olwin
Keyword(s):  
Complex Formation ◽  
Protein Interactions ◽  
Calcium Ions ◽  
Fixed Number ◽  
Factor V ◽  
Clotting Factors ◽  
Number Of Binding Sites ◽  
C Complex ◽  
Autoprothrombin C

SummarySince Ac-globulin (factor V) is involved in the formation of prothrombin activator, its ability to complex with phospholipids was studied. Purified bovine Ac-globulin was complexed to asolectin, there being presumably a fixed number of binding sites on the phospholipid micelle for Ac-globulin. In contrast to the requirement for calcium ions in the formation of complexes between asolectin and autoprothrombin C, calcium ions were not required for complex formation between asolectin and Ac-globulin to occur ; in fact, the presence of calcium prevented complex formation occurring, the degree of inhibition being dependent on the calcium concentration. By treating isolated, pre-formed aso- lectin-Ac-globulin complexes with calcium chloride solutions, Ac-globulin could be recovered in a much higher state of purity and essentially free of asolectin.Complete activators were formed by first preparing the asolectin-calcium- autoprothrombin C complex and then reacting the complex with Ac-globulin. A small amount of this product was very effective as an activator of purified prothrombin without further addition of calcium or any other cofactor. If the autoprothrombin C preparation used to prepare the complex was free of traces of prothrombin, the complete activator was stable for several hours at room temperature. Stable preparations of the complete activator were centrifuged, resulting in the sedimentation of most of the activity. Experimental evidence also indicated that activator activity was highest when autoprothrombin C and Ac-globulin were complexed to the same phospholipid micelle, rather than when the two clotting factors were complexed to separate micelles. These data suggested that the in vivo prothrombin activator may be a sedimentable complex composed of a thromboplastic enzyme, calcium, Ac-globulin and phospholipid.

Proton MR Spectroscopic Features of the Human Liver: In-Vivo Application to the Normal Condition

1999 ◽  
Vol 40 (1) ◽  
pp. 77
Author(s):  
Soon Gu Cho ◽  
Mi Young Kim ◽  
Young Soo Kim ◽  
Won Choi ◽  
Seok Hwan Shin ◽  
...  
Keyword(s):  
Normal Condition ◽  
Human Liver

Probing the 14-3-3 Isoform-Specificity Profile of Interactions Stabilized by Fusicoccin A

2020 ◽  
Author(s):  
James Frederich ◽  
Ananya Sengupta ◽  
Josue Liriano ◽  
Ewa A. Bienkiewicz ◽  
Brian G. Miller
Keyword(s):  
Protein Interactions ◽  
Neurological Diseases ◽  
Adapter Proteins ◽  
Protein Protein Interactions ◽  
Specific Expression ◽  
Individual Client ◽  
Isoform Specificity ◽  
Fusicoccin A

Fusicoccin A (FC) is a fungal phytotoxin that stabilizes protein–protein interactions (PPIs) between 14-3-3 adapter proteins and their phosphoprotein interaction partners. In recent years, FC has emerged as an important chemical probe of human 14-3-3 PPIs implicated in cancer and neurological diseases. These previous studies have established the structural requirements for FC-induced stabilization of 14-3-3·client phosphoprotein complexes; however, the effect of different 14-3-3 isoforms on FC activity has not been systematically explored. This is a relevant question for the continued development of FC variants because there are seven distinct isoforms of 14-3-3 in humans. Despite their remarkable sequence and structural similarities, a growing body of experimental evidence supports both tissue-specific expression of 14-3-3 isoforms and isoform-specific functions <i>in vivo</i>. Herein, we report the isoform-specificity profile of FC <i>in vitro</i>using recombinant human 14-3-3 isoforms and a focused library of fluorescein-labeled hexaphosphopeptides mimicking the C-terminal 14-3-3 recognition domains of client phosphoproteins targeted by FC in cell culture. Our results reveal modest isoform preferences for individual client phospholigands and demonstrate that FC differentially stabilizes PPIs involving 14-3-3s. Together, these data provide strong motivation for the development of non-natural FC variants with enhanced selectivity for individual 14-3-3 isoforms.

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