Cell surface anchorage and ligand-binding domains of the Saccharomyces cerevisiae cell adhesion protein alpha-agglutinin, a member of the immunoglobulin superfamily

1993 ◽  
Vol 13 (4) ◽  
pp. 2554-2563
Author(s):  
D Wojciechowicz ◽  
C F Lu ◽  
J Kurjan ◽  
P N Lipke

alpha-Agglutinin is a cell adhesion glycoprotein expressed on the cell wall of Saccharomyces cerevisiae alpha cells. Binding of alpha-agglutinin to its ligand a-agglutinin, expressed by a cells, mediates cell-cell contact during mating. Analysis of truncations of the 650-amino-acid alpha-agglutinin structural gene AG alpha 1 delineated functional domains of alpha-agglutinin. Removal of the C-terminal hydrophobic sequence allowed efficient secretion of the protein and loss of cell surface attachment. This cell surface anchorage domain was necessary for linkage to a glycosyl phosphatidylinositol anchor. A construct expressing the N-terminal 350 amino acid residues retained full a-agglutinin-binding activity, localizing the binding domain to the N-terminal portion of alpha-agglutinin. A 278-residue N-terminal peptide was inactive; therefore, the binding domain includes residues between 278 and 350. The segment of alpha-agglutinin between amino acid residues 217 and 308 showed significant structural and sequence similarity to a consensus sequence for immunoglobulin superfamily variable-type domains. The similarity of the alpha-agglutinin-binding domain to mammalian cell adhesion proteins suggests that this structure is a highly conserved feature of adhesion proteins in diverse eukaryotes.

1993 ◽  
Vol 13 (4) ◽  
pp. 2554-2563 ◽  
Author(s):  
D Wojciechowicz ◽  
C F Lu ◽  
J Kurjan ◽  
P N Lipke

alpha-Agglutinin is a cell adhesion glycoprotein expressed on the cell wall of Saccharomyces cerevisiae alpha cells. Binding of alpha-agglutinin to its ligand a-agglutinin, expressed by a cells, mediates cell-cell contact during mating. Analysis of truncations of the 650-amino-acid alpha-agglutinin structural gene AG alpha 1 delineated functional domains of alpha-agglutinin. Removal of the C-terminal hydrophobic sequence allowed efficient secretion of the protein and loss of cell surface attachment. This cell surface anchorage domain was necessary for linkage to a glycosyl phosphatidylinositol anchor. A construct expressing the N-terminal 350 amino acid residues retained full a-agglutinin-binding activity, localizing the binding domain to the N-terminal portion of alpha-agglutinin. A 278-residue N-terminal peptide was inactive; therefore, the binding domain includes residues between 278 and 350. The segment of alpha-agglutinin between amino acid residues 217 and 308 showed significant structural and sequence similarity to a consensus sequence for immunoglobulin superfamily variable-type domains. The similarity of the alpha-agglutinin-binding domain to mammalian cell adhesion proteins suggests that this structure is a highly conserved feature of adhesion proteins in diverse eukaryotes.


Author(s):  
Huichao Wang ◽  
Tong Zhao ◽  
Shuhui Yang ◽  
Liang Zou ◽  
Xiaolong Wang ◽  
...  

Abstract Under the severe situation of the current global epidemic, researchers have been working hard to find a reliable way to suppress the infection of the virus and prevent the spread of the epidemic. Studies have shown that the recognition and binding of human angiotensin-converting enzyme 2 (ACE2) by the receptor-binding domain (BRD) of spike protein on the surface of SARS-CoV-2 is a crucial step for SARS-CoV-2 to invade human receptor cells, and blocking this process can inhibit the virus from invading human normal cells. Plasma treatment can disrupt the structure of the RBD and effectively block the binding process. However, the mechanism by which plasma blocks the recognition and binding between the two is not clear. In this study, reaction process between reactive oxygen species (ROS) in plasma and the molecular model of RBD was simulated using a reactive molecular dynamics method. The results showed that the destruction of RBD molecule by ROS was triggered by hydrogen abstraction reactions. O and OH abstracted H atoms from RBD, while the H atoms of H2O2 and HO2 were abstracted by RBD. The hydrogen abstraction resulted in the breakage of C-H, N-H, O-H and C=O bonds and the formation of C=C, C=N bonds. The addition reaction of OH increased the number of O-H bonds and caused the formation of C-O, N-O and O-H bonds. The dissociation of N-H bonds led to the destruction of the original structure of peptide bonds and amino acid residues, change the type of amino acid residues, and caused the conversion of N-C and N=C, C=O and C-O. The simulation partially elucidated the microscopic mechanism of the interaction between ROS in plasma and the capsid protein of SARS-CoV-2, providing theoretical support for the control of SARS-CoV-2 infection by plasma, a contribution to overcoming the global epidemic problem.


2003 ◽  
Vol 14 (11) ◽  
pp. 4342-4351 ◽  
Author(s):  
Huamin Wang ◽  
Xiaodong Wang ◽  
Yu Jiang

In Saccharomyces cerevisiae, Pph21 and Pph22 are the two catalytic subunits of type 2A phosphatase (PP2Ac), and Sit4 is a major form of 2A-like phosphatase. The function of these phosphatases requires their association with different regulatory subunits. In addition to the conventional regulatory subunits, namely, the A and B subunits for Pph21/22 and the Sap proteins for Sit4, these phosphatases have been found to associate with a protein termed Tap42. In this study, we demonstrated that Sit4 and PP2Ac interact with Tap42 via an N-terminal domain that is conserved in all type 2A and 2A-like phosphatases. We found that the Sit4 phosphatase in the sit4-102 strain contains a reverse-of-charge amino acid substitution within its Tap42 binding domain and is defective for formation of the Tap42-Sit4 complex. Our results suggest that the interaction with Tap42 is required for the activity as well as for the essential function of Sit4 and PP2Ac. In addition, we showed that Tap42 is able to interact with two other 2A-like phosphatases, Pph3 and Ppg1.


Cells ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1503 ◽  
Author(s):  
Hintermann ◽  
Christen

Fibrogenesis is a progressive scarring event resulting from disrupted regular wound healing due to repeated tissue injury and can end in organ failure, like in liver cirrhosis. The protagonists in this process, either liver-resident cells or patrolling leukocytes attracted to the site of tissue damage, interact with each other by soluble factors but also by direct cell–cell contact mediated by cell adhesion molecules. Since cell adhesion molecules also support binding to the extracellular matrix, they represent excellent biosensors, which allow cells to modulate their behavior based on changes in the surrounding microenvironment. In this review, we focus on selectins, cadherins, integrins and members of the immunoglobulin superfamily of adhesion molecules as well as some non-classical cell adhesion molecules in the context of hepatic fibrosis. We describe their liver-specific contributions to leukocyte recruitment, cell differentiation and survival, matrix remodeling or angiogenesis and touch on their suitability as targets in antifibrotic therapies.


2005 ◽  
Vol 25 (3) ◽  
pp. 1003-1012 ◽  
Author(s):  
Naomi Yoshida ◽  
Takehiro Ogata ◽  
Kenji Tanabe ◽  
Songhua Li ◽  
Megumi Nakazato ◽  
...  

ABSTRACT The heterodimeric transcription factor PEBP2/CBF is composed of a DNA-binding subunit, called Runx1, and a non-DNA-binding subunit, called PEBP2β/CBFβ. The Runx1 protein is detected exclusively in the nuclei of most cells and tissues, whereas PEBP2β is located in the cytoplasm. We addressed the mechanism by which PEBP2β localizes to the cytoplasm and found that it is associated with filamin A, an actin-binding protein. Filamin A retains PEBP2β in the cytoplasm, thereby hindering its engagement as a Runx1 partner. The interaction with filamin A is mediated by a region within PEBP2β that includes amino acid residues 68 to 93. The deletion of this region or the repression of filamin A enables PEBP2β to translocate to the nucleus. Based on these observations, we propose that PEBP2β has two distinct domains, a newly defined regulatory domain that interacts with filamin A and the previously identified Runx1-binding domain.


2000 ◽  
Vol 182 (23) ◽  
pp. 6732-6741 ◽  
Author(s):  
Yumiko Takatsuka ◽  
Yoshihiro Yamaguchi ◽  
Minenobu Ono ◽  
Yoshiyuki Kamio

ABSTRACT Lysine decarboxylase (LDC; EC 4.1.1.18 ) from Selenomonas ruminantium comprises two identical monomeric subunits of 43 kDa and has decarboxylating activities toward both l-lysine andl-ornithine with similar Km andVmax values (Y. Takatsuka, M. Onoda, T. Sugiyama, K. Muramoto, T. Tomita, and Y. Kamio, Biosci. Biotechnol. Biochem. 62:1063–1069, 1999). Here, the LDC-encoding gene (ldc) of this bacterium was cloned and characterized. DNA sequencing analysis revealed that the amino acid sequence of S. ruminantium LDC is 35% identical to those of eukaryotic ornithine decarboxylases (ODCs; EC 4.1.1.17 ), including the mouse,Saccharomyces cerevisiae, Neurospora crassa,Trypanosoma brucei, and Caenorhabditis elegansenzymes. In addition, 26 amino acid residues, K69, D88, E94, D134, R154, K169, H197, D233, G235, G236, G237, F238, E274, G276, R277, Y278, K294, Y323, Y331, D332, C360, D361, D364, G387, Y389, and F397 (mouse ODC numbering), all of which are implicated in the formation of the pyridoxal phosphate-binding domain and the substrate-binding domain and in dimer stabilization with the eukaryotic ODCs, were also conserved inS. ruminantium LDC. Computer analysis of the putative secondary structure of S. ruminantium LDC showed that it is approximately 70% identical to that of mouse ODC. We identified five amino acid residues, A44, G45, V46, P54, and S322, within the LDC catalytic domain that confer decarboxylase activities toward bothl-lysine and l-ornithine with a substrate specificity ratio of 0.83 (defined as thek cat/Km ratio obtained with l-ornithine relative to that obtained withl-lysine). We have succeeded in converting S. ruminantium LDC to form with a substrate specificity ratio of 58 (70 times that of wild-type LDC) by constructing a mutant protein, A44V/G45T/V46P/P54D/S322A. In this study, we also showed that G350 is a crucial residue for stabilization of the dimer in S. ruminantium LDC.


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