Faculty Opinions recommendation of Glypicans shield the Wnt lipid moiety to enable signalling at a distance.

Author(s):  
Rik Korswagen
Keyword(s):  
1994 ◽  
Vol 266 (6) ◽  
pp. C1684-C1691 ◽  
Author(s):  
M. Berg ◽  
S. Offermanns ◽  
R. Seifert ◽  
G. Schultz

Lipopeptide analogues of the NH2-terminus of bacterial lipoprotein are known to induce activation of macrophages, neutrophils, and lymphocytes. We studied the effect of the lipopeptide N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteinyl-( S)-seryl-(S)-lysyl-(S)-lysyl-(S)-lysyl-(S)-lysine [Pam3CysSer(Lys)4] on several functions of human platelets. Pam3CysSer(Lys)4 led to the aggregation of platelets and induced the secretion of serotonin with an effectiveness similar to thrombin. These cellular effects of Pam3CysSer(Lys)4 were concentration dependent, being half maximal at 2-3 microM and maximal at 10-30 microM. Another lipopeptide also induced platelet aggregation and serotonin secretion but was less potent and less effective than Pam3CysSer(Lys)4. The lipid moiety and the peptide moiety of Pam3CysSer(Lys)4 alone were without any effect. Lipopeptides also stimulated tyrosine phosphorylation of several proteins with molecular masses similar to those found to be tyrosine phosphorylated in response to thrombin, and Pam3CysSer(Lys)4 led to an increase in the cytosolic calcium concentration. All studied responses of platelets to lipopeptides were inhibited by the prostacyclin receptor agonist cicaprost. Taken together, our data show that lipopeptides are effective activators of human platelets and that this activation is susceptible to the action of physiological platelet inhibitors.


2021 ◽  
Vol 22 (2) ◽  
pp. 701
Author(s):  
Tomasz K Gozdziewicz ◽  
Anna Maciejewska ◽  
Alona Tsybulska ◽  
Czeslaw Lugowski ◽  
Jolanta Lukasiewicz

Enterobacterial common antigen (ECA) is a conserved antigen expressed by enterobacteria. It is built by trisaccharide repeating units: →3)-α-D-Fucp4NAc-(1→4)-β-D-ManpNAcA-(1→4)-α-D-GlcpNAc-(1→ and occurs in three forms: as surface-bound linear polysaccharides linked to a phosphoglyceride (ECAPG) or lipopolysaccharide − endotoxin (ECALPS), and cyclic form (ECACYC). ECA maintains, outer membrane integrity, immunogenicity, and viability of enterobacteria. A supernatant obtained after LPS ultracentrifugation was reported as a source for ECA isolation, but it has never been assessed for detailed composition besides ECACYC. We used mild acid hydrolysis and gel filtration, or zwitterionic-hydrophilic interaction liquid (ZIC®HILIC) chromatography combined with mass spectrometry for purification, fractionation, and structural analysis of rough Shigella sonnei and Escherichia coli R1 and K12 crude LPS preparations. Presented work is the first report concerning complex characteristic of all ECA forms present in LPS-derived supernatants. We demonstrated high heterogeneity of the supernatant-derived ECA that contaminate LPS purified by ultracentrifugation. Not only previously reported O-acetylated tetrameric, pentameric, and hexameric ECACYC have been identified, but also devoid of lipid moiety linear ECA built from 7 to 11 repeating units. Described results were common for all selected strains. The origin of linear ECA is discussed against the current knowledge about ECAPG and ECALPS.


Blood ◽  
1998 ◽  
Vol 91 (5) ◽  
pp. 1784-1792 ◽  
Author(s):  
Gianluca Civenni ◽  
Samuel T. Test ◽  
Urs Brodbeck ◽  
Peter Bütikofer

Abstract In many different cells, glycosylphosphatidylinositol (GPI)-anchored molecules are clustered in membrane microdomains that resist extraction by detergents at 4°C. In this report, we identified the presence of such domains in human erythrocytes and examined the ability of exogenously-added GPI-anchored molecules to colocalize with the endogenous GPI-anchored proteins in these detergent-insoluble complexes. We found that the addition to human erythrocytes of three purified GPI-anchored proteins having different GPI lipid moieties resulted in their efficient and correct incorporation into the membrane. The extent of membrane insertion was dependent on the intactness of the GPI lipid moiety. However, unlike the endogenous GPI-anchored proteins, the in vitro incorporated GPI molecules were not resistant to membrane extraction by Triton X-100 at 4°C. In addition, in contrast to the endogenous GPI-anchored proteins, they were not preferentially released from erythrocytes during vesiculation induced by calcium loading of the cells. These results suggest that in vitro incorporated GPI-linked molecules are excluded from pre-existing GPI-enriched membrane areas in human erythrocytes and that these microdomains may represent the sites of membrane vesicle formation.


1986 ◽  
Vol 40 (1) ◽  
pp. 71-86 ◽  
Author(s):  
Domenico Acquotti ◽  
Sandro Sonnino ◽  
Massimo Masserini ◽  
Luigi Casella ◽  
Giovanni Fronza ◽  
...  

Nature ◽  
2020 ◽  
Vol 585 (7823) ◽  
pp. 85-90 ◽  
Author(s):  
Ian J. McGough ◽  
Luca Vecchia ◽  
Benjamin Bishop ◽  
Tomas Malinauskas ◽  
Karen Beckett ◽  
...  
Keyword(s):  

2018 ◽  
Vol 23 (10) ◽  
pp. 880-892 ◽  
Author(s):  
Takehiko Yoko-o ◽  
Mariko Umemura ◽  
Akiko Komatsuzaki ◽  
Kazutaka Ikeda ◽  
Daisuke Ichikawa ◽  
...  

1980 ◽  
Vol 187 (3) ◽  
pp. 851-856 ◽  
Author(s):  
G Vallette ◽  
C Benassayag ◽  
L Savu ◽  
J Delorme ◽  
E A Nunez ◽  
...  

The novel endogenous serum ligands of rat alpha 1-foetoprotein previously demonstrated in different mammalian sera were identified by g.l.c.–mass-spectrometric methods as a mixture of non-esterified long-chain and predominantly unsaturated fatty acids. Detailed comparative analyses of these ligands extracted from foetal- and pregnant-rat sera, rat amniotic fluid and foetal human sera are presented. We also show that an important fraction of these ligands remains associated with the rat alpha 1-foetoprotein after purification; analyses are given for the composition of this lipid moiety of the foetoprotein. The physiological relevance of these results is discussed.


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