The complex understanding of Annexin A1 phosphorylation.

Abstract Annexin A1 (ANXA1) is the first characterized member of the annexins superfamily. It binds the cellular membrane phospholipids in Ca2 + regulated manner. Annexin A1 has been found in several tissues and many physiological roles as hormones secretion, vesiculation, inflammatory response, apoptosis and differentiation have been shown. Its subcellular localization and binding with many partner proteins are altered accordingly with its physiological role. The Annexin A1 membrane localization is crucial for binding to receptors, suggesting a paracrine and juxtacrine extracellular action. Annexin A1 is subjected to several post-translational modifications. In particular the protein is phosphorylated on several residues both on the N-terminal functional domain and on the C-terminus core. Different kinases have been identified as responsible for the phosphorylation status of selective residues. The specific change in the phosphorylation status on the different sites alters ANXA1 localization, binding properties and functions. This review shows the physiological relevance of the ANXA1 phosphorylation leading to the conclusion that numerous and different roles of Annexin A1 could be associated with different phosphorylations to alter not only intracellular localization and bindings to its partners but also the extracellular receptor interactions

POTENTIAL CELL PROLIFERATION INHIBITOR ISOLATED FROM INDONESIAN BROWN ALGAE (PHAEOPHYTA)

Objective: The objective of this study is to determine the toxic activity of n-hexane and ethyl acetate extracts of brown algae as anticancer candidates.Methods: The brown algae were collected from West Java south coast, identified and then dried. The dry algae was then extracted by using n-hexane and ethyl acetate, filtered, then dried. The toxic activity of n-hexane and ethyl acetate extracts of five species brown algae was screened by using the brine shrimp lethality test (BSLT). The detection for chemical compound was carried out by placing the extracts on a Thin Layer Chromatography (TLC) plate and spraying them with several spray reagents such as Dragendorff, Citro boric acid, and vanillin-sulfuric acid.Results: We identified five species of brown algae i.e.: Sargassum sp., Sargassum duplicatum J. G. Agardh, Sargassum myriocystum J. G. Agardh, Turbinaria ornata (Turner) J. G. Agardh, and Turbinaria decurrens Bory. Four of ten extracts had toxic activities, i.e.: n-hexane extract of Sargassum myriocystum J. G. Agardh (LC50= 273.28 µg/ml), n-hexane extract of Turbinaria ornata (Turner) J. G. Agardh (LC50= 320.4 µg/ml), n-hexane extract of Turbinaria decurrens Bory (LC50= 579.33 µg/ml), and the ethyl acetate extract of Sargassum sp. (LC50= 743.98 µg/ml), whereas Sargassum duplicatum J. G. Agardh was found to be less toxic (nontoxic) (LC50>1000 µg/ml). The active compound of this alga was detected in TLC is terpenoid.Conclusions: N-hexane extract of Sargassum myriocystum J. G. Agardh showed the highest toxicity in the brine shrimp assay (LC50= 273.28 µg/ml).Â

EFFECT OF FEEDING WITH HERB OF ERYTHRINA VARIEGATA TO BIOCOMPATIBILITY OF THE COCOON FIBER OF WILD SILK MOTH ATTACUS ATLAS FOR FUTURE APPLICATION AS BIOCOMPATIBLE OF SILK SUTURES

Objectives: Silk is biocompatible as biomaterial and has been used commercially as sutures. More interesting properties of the silk are that the mechanical properties exceed all natural polymer and synthetic materials. In this research, a type of silk suture is being developed from species of Attacus atlas to obtain better biocompatible sutures. A. atlas is a species of silk moth that consume not only single types of leaves. The Quality of cocoon fiber then can be arranged base on the types of the leaves that is consumed. Better biocompatibility sutures comparing with recent commercial silk sutures which is not biocompatible, can be achieved by feeding with variety types of leaves. Silk suture that already established in the market is a base product of Bombyx mori species of silk which is only consume one type of leaf (mulberry leaves).Methods: In this research, the A. atlas cocoon was produced by feeding with herb Erythrina variegate. The microstructure was observed, element composition as well as biocompatibles properties was investigated.Results: A high composition of kalium (K) as well as chloride (Cl) is identified in the fiber. The released fiber from cocoon also indicates high biocompatibility that is promising as biocompatible suture.Conclusion: The biocompatible fiber for future application as sutures is possible to be prepared by feeding the wild silkworm of A. atlas with leaf of E. variegate. The fiber is found rich with kalium (K) as well as chloride (Cl) with irregular shape of crystal at the surface of the fiber

The Present and Future of Virology in the Czech Republic—A New Phoenix Made of Ashes?

The Czech Republic, a part of the former Czechoslovakia, has been at the forefront of several research directions in virology, genetics and physiology [...

Surface Display of Metal Fixation Motifs of Bacterial P1-Type ATPases Specifically Promotes Biosorption of Pb2+ by Saccharomyces cerevisiae▿

Biosorption of metal ions may take place by different passive metal-sequestering processes such as ion exchange, complexation, physical entrapment, and inorganic microprecipitation or by a combination of these. To improve the biosorption capacity of the potential yeast biosorbent, short metal-binding NP peptides (harboring the CXXEE metal fixation motif of the bacterial Pb2+-transporting P1-type ATPases) were efficiently displayed and covalently anchored to the cell wall of Saccharomyces cerevisiae. These were fusions to the carboxyl-terminal part of the sexual adhesion glycoprotein α-agglutinin (AGα1Cp). Compared to yeast cells displaying the anchoring domain only, those having a surface display of NP peptides multiplied their Pb2+ biosorption capacity from solutions containing a 75 to 300 μM concentration of the metal ion up to 5-fold. The S-type Pb2+ biosorption isotherms, plus the presence of electron-dense deposits (with an average size of 80 by 240 nm, observed by transmission electron microscopy) strongly suggested that the improved biosorption potential of NP-displaying cells is due to the onset of microprecipitation of Pb species on the modified cell wall. The power of an improved capacity for Pb biosorption was also retained by the isolated cell walls containing NP peptides. Their Pb2+ biosorption property was insensitive to the presence of a 3-fold molar excess of either Cd2+ or Zn2+. These results suggest that the biosorption mechanism can be specifically upgraded with microprecipitation by the engineering of the biosorbent with an eligible metal-binding peptide

Molecular Organization of Mason-Pfizer Monkey Virus Capsids Assembled from Gag Polyprotein in Escherichia coli

We describe the results of a study by electron microscopy and image processing of Gag protein shells—immature capsids—of Mason-Pfizer monkey virus assembled in Escherichia coli from two truncated forms of the Gag precursor: Δp4Gag, in which the C-terminal p4Gag was deleted, and Pro(−)CA.NC, in which the N-terminal peptides and proline 1 of the CA domain were deleted. Negative staining of capsids revealed small patches of holes forming a trigonal or hexagonal pattern most clearly visible on occasional tubular forms. The center-to-center spacing of holes in the network was 7.1 nm in Δp4Gag capsids and 7.4 nm in Pro(−)CA.NC capsids. Image processing of Δp4Gag tubes revealed a hexagonal network of holes formed by six subunits with a single subunit shared between rings. This organization suggests that the six subunits are contributed by three trimers of the truncated Gag precursor. Similar molecular organization was observed in negatively stained Pro(−)CA.NC capsids. Shadowed replicas of freeze-etched capsids produced by either construct confirmed the presence of a hexagonal network of holes with a similar center-to-center spacing. We conclude that the basic building block of the cage-like network is a trimer of the Δp4Gag or Pro(−)CA.NC domains. In addition, our results point to a key role of structurally constrained CA domain in the trimeric interaction of the Gag polyprotein