Contact inhibition of locomotion and the structure of homotypic and heterotypic intercellular contacts in embryonic epithelial cultures

1981 ◽  
Vol 135 (1) ◽  
pp. 93-102 ◽  
Author(s):  
E.J. Sanders ◽  
S. Prasad
Author(s):  
G Gogichadze ◽  
T Gogichadze ◽  
E Mchedlishvili

As is known, the superficial charge of most somatic cells is negative. Proceeding from this fact, somatic cells never interact. There is always some type of space (intercellular space) between them. Intercellular contacts are predominantly determined by two main factors: Van der Waals (positive taxis) and electrostatic (negative taxis) forces contributing to the formation of membrane electric potential. Presence of the intercellular space is a structural representation of the balance bet­ween these forces (contact inhibition).


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lukas Wettstein ◽  
Tatjana Weil ◽  
Carina Conzelmann ◽  
Janis A. Müller ◽  
Rüdiger Groß ◽  
...  

AbstractSARS-CoV-2 is a respiratory pathogen and primarily infects the airway epithelium. As our knowledge about innate immune factors of the respiratory tract against SARS-CoV-2 is limited, we generated and screened a peptide/protein library derived from bronchoalveolar lavage for inhibitors of SARS-CoV-2 spike-driven entry. Analysis of antiviral fractions revealed the presence of α1-antitrypsin (α1AT), a highly abundant circulating serine protease inhibitor. Here, we report that α1AT inhibits SARS-CoV-2 entry at physiological concentrations and suppresses viral replication in cell lines and primary cells including human airway epithelial cultures. We further demonstrate that α1AT binds and inactivates the serine protease TMPRSS2, which enzymatically primes the SARS-CoV-2 spike protein for membrane fusion. Thus, the acute phase protein α1AT is an inhibitor of TMPRSS2 and SARS-CoV-2 entry, and may play an important role in the innate immune defense against the novel coronavirus. Our findings suggest that repurposing of α1AT-containing drugs has prospects for the therapy of COVID-19.


2019 ◽  
Vol 20 (8) ◽  
pp. 1996 ◽  
Author(s):  
Katharine A. Michie ◽  
Adam Bermeister ◽  
Neil O. Robertson ◽  
Sophia C. Goodchild ◽  
Paul M. G. Curmi

The merlin-ERM (ezrin, radixin, moesin) family of proteins plays a central role in linking the cellular membranes to the cortical actin cytoskeleton. Merlin regulates contact inhibition and is an integral part of cell–cell junctions, while ERM proteins, ezrin, radixin and moesin, assist in the formation and maintenance of specialized plasma membrane structures and membrane vesicle structures. These two protein families share a common evolutionary history, having arisen and separated via gene duplication near the origin of metazoa. During approximately 0.5 billion years of evolution, the merlin and ERM family proteins have maintained both sequence and structural conservation to an extraordinary level. Comparing crystal structures of merlin-ERM proteins and their complexes, a picture emerges of the merlin-ERM proteins acting as switchable interaction hubs, assembling protein complexes on cellular membranes and linking them to the actin cytoskeleton. Given the high level of structural conservation between the merlin and ERM family proteins we speculate that they may function together.


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