scholarly journals Protein production, crystallization and preliminary crystallographic analysis of the four N-terminal immunoglobulin domains of Down syndrome cell adhesion molecule 1

2015 ◽  
Vol 71 (6) ◽  
pp. 775-778 ◽  
Author(s):  
Linna Cheng ◽  
Shu-Ang Li ◽  
Yamei Yu ◽  
Qiang Chen
Keyword(s):  
Down Syndrome ◽  
Cell Adhesion ◽  
Adhesion Molecule ◽  
Rna Splicing ◽  
Cell Adhesion Molecule ◽  
Crystallographic Analysis ◽  
Homophilic Binding ◽  
Ig Superfamily ◽  
Cell Adhesion Molecule 1 ◽  
Insight Into

Down syndrome cell adhesion molecule 1 (Dscam1), a member of the immunoglobulin (Ig) superfamily, plays important roles in both the nervous and the immune systems. Via alternative RNA splicing,DrosophilaDscam1 encodes a vast family of Ig-containing proteins that exhibit isoform-specific homophilic binding. Whether different Dscam1 isoforms adopt the same dimerization mode is under debate, and the detailed mechanism of Dscam1 specificity remains unclear. In this study, eight different isforms of Dscam1 Ig1–4 have been cloned, overexpressed, purified to homogeneity and crystallized. X-ray data were collected to 1.9–4.0 Å resolution. These structures will provide the opportunity to perform extensive structural comparisons of different Dscam1 isoforms and provide insight into its specificity.

scholarly journals Atomic Level Dissection of the Platelet Endothelial Cell Adhesion Molecule 1 (PECAM-1) Homophilic Binding Interface: Implications for Endothelial Cell Barrier Function

2021 ◽  
Author(s):  
Danying Liao ◽  
Jesse Sundlov ◽  
Jieqing Zhu ◽  
Heng Mei ◽  
Yu Hu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Cell Adhesion ◽  
Endothelial Cell ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Homophilic Binding ◽  
Endothelial Cell Adhesion Molecule ◽  
Platelet Endothelial Cell Adhesion ◽  
Cell Adhesion Molecule 1 ◽  
Endothelial Cell Adhesion

Objective: PECAM-1 (platelet endothelial cell adhesion molecule 1) is a 130 kDa member of the immunoglobulin (Ig) gene superfamily that is expressed on the surfaces of platelets and leukocytes and concentrated at the intercellular junctions of confluent endothelial cell monolayers. PECAM-1 Ig domains 1 and 2 (IgD1 and IgD2) engage in homophilic interactions that support a host of vascular functions, including support of leukocyte transendothelial migration and the maintenance of endothelial junctional integrity. The recently solved crystal structure of PECAM-1 IgD1 and IgD2 revealed a number of intermolecular interfaces predicted to play important roles in stabilizing PECAM-1/PECAM-1 homophilic interactions and in formation and maintenance of endothelial cell-cell contacts. We sought to determine whether the protein interfaces implicated in the crystal structure reflect physiologically important interactions. Approach and Results: We assessed the impact of single amino acid substitutions at the interfaces between opposing PECAM-1 molecules on homophilic binding and endothelial cell function. Substitution of key residues within the IgD1-IgD1 and IgD1-IgD2 interfaces but not those within the smaller IgD2-IgD2 interface, markedly disrupted PECAM-1 homophilic binding and its downstream effector functions, including the ability of PECAM-1 to localize at endothelial cell-cell borders, mediate the formation of endothelial tubes, and restore endothelial barrier integrity. Conclusions: Taken together, these results validate the recently described PECAM-1 IgD1/IgD2 crystal structure by demonstrating that specific residues visualized within the IgD1-IgD1 and IgD1-IgD2 interfaces of opposing molecules in the crystal are required for functionally important homophilic interactions. This information can now be exploited to modulate functions of PECAM-1 in vivo.

scholarly journals Protein production, crystallization and preliminary X-ray analysis of two isoforms of the Dscam1 Ig7 domain

2015 ◽  
Vol 71 (3) ◽  
pp. 330-332
Author(s):  
Shu-Ang Li ◽  
Linna Cheng ◽  
Yamei Yu ◽  
Qiang Chen
Keyword(s):  
Down Syndrome ◽  
Neural Development ◽  
Rna Splicing ◽  
Cell Adhesion Molecule ◽  
Protein Production ◽  
Critical Role ◽  
X Ray ◽  
Homophilic Interaction ◽  
Cell Adhesion Molecule 1 ◽  
Insight Into

DrosophilaDown syndrome cell adhesion molecule 1 (Dscam1) plays a critical role in neural development. It can potentially form 38 016 isoforms through alternative RNA splicing, and exhibits isoform-specific homophilic interaction through three variable Ig domains (Ig2, Ig3 and Ig7). The diversity and homophilic interaction are essential for its functions. Ig7 has 33 isoforms and is the most variable among the three variable Ig domains. However, only one isoform of Ig7 (isoform 30) has been structurally determined to date. Here, two isoforms of Dscam1 Ig7 (isoforms 5 and 9; Ig75and Ig79) were produced and crystallized. Diffraction data from Ig75and Ig79crystals were processed to resolutions of 1.95 and 2.37 Å, respectively. Comparison of different Dscam1 Ig7 isoforms will provide insight into the mechanism of its binding specificity.

scholarly journals Organization of the gene for human platelet/endothelial cell adhesion molecule-1 shows alternatively spliced isoforms and a functionally complex cytoplasmic domain

Blood ◽  
1994 ◽  
Vol 84 (12) ◽  
pp. 4028-4037 ◽  
Author(s):  
NE Kirschbaum ◽  
RJ Gumina ◽  
PJ Newman
Keyword(s):  
Cell Adhesion ◽  
Endothelial Cell ◽  
Human Chromosome ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Cytoplasmic Domain ◽  
Platelet Endothelial Cell Adhesion ◽  
Ig Superfamily ◽  
Cell Adhesion Molecule 1 ◽  
Endothelial Cell Adhesion

Platelet endothelial cell adhesion molecule-1 (PECAM-1) is a cell-cell adhesion molecule that is expressed on circulating platelets, on leukocytes, and at the intercellular junctions of vascular endothelial cells and mediates the interactions of these cells during the process of transendothelial cell migration. The cDNA for PECAM-1 encodes an open reading frame of 738 amino acids (aa) that is organized into a 27- aa signal peptide, a 574-aa extracellular domain composed of 6 Ig homology units, and a relatively long cytoplasmic tail of 118 aa containing multiple sites for posttranslational modification and postreceptor signal transduction. To provide a molecular basis for the precise evaluation of the structure and function of this transmembrane glycoprotein, we have determined the organization of the human PECAM-1 gene. The PECAM-1 gene, which has been localized to human chromosome 17, is a single-copy gene of approximately 65 kb in length and is broken into 16 exons by introns ranging in size from 86 to greater than 12,000 bp in length. Typical of other members of the Ig superfamily, each of the extracellular Ig homology domains is encoded by a separate exon, consistent with PECAM-1 having arisen by gene duplication and exon shuffling of ancestral Ig superfamily genes. However, the cytoplasmic domain was found to be surprisingly complex, being encoded by seven short exons that may represent discrete functional entities. Alternative splicing of the cytoplasmic tail appears to generate multiple PECAM-1 isoforms that may regulate phosphorylation, cytoskeletal association, and affinity modulation of the mature protein. Finally, a processed pseudogene having 76% identity with PECAM- 1 cDNA was identified and localized to human chromosome 3. These findings should have important implications for structure/function analysis of PECAM-1 and its role in vascular adhesive interactions.

scholarly journals Down syndrome cell adhesion molecule 1 : testing for a role in insect immunity, behaviour and reproduction

2016 ◽  
Vol 3 (4) ◽  
pp. 160138 ◽  
Author(s):  
Robert Peuß ◽  
Kristina U. Wensing ◽  
Luisa Woestmann ◽  
Hendrik Eggert ◽  
Barbara Milutinović ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Cell Adhesion ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Insect Immunity ◽  
Short Term ◽  
Males And Females ◽  
Neuronal Functions ◽  
Cell Adhesion Molecule 1

Down syndrome cell adhesion molecule 1 ( Dscam1 ) has wide-reaching and vital neuronal functions although the role it plays in insect and crustacean immunity is less well understood. In this study, we combine different approaches to understand the roles that Dscam1 plays in fitness-related contexts in two model insect species. Contrary to our expectations, we found no short-term modulation of Dscam1 gene expression after haemocoelic or oral bacterial exposure in Tribolium castaneum , or after haemocoelic bacterial exposure in Drosophila melanogaster. Furthermore, RNAi-mediated Dscam1 knockdown and subsequent bacterial exposure did not reduce T. castaneum survival. However, Dscam1 knockdown in larvae resulted in adult locomotion defects, as well as dramatically reduced fecundity in males and females. We suggest that Dscam1 does not always play a straightforward role in immunity, but strongly influences behaviour and fecundity. This study takes a step towards understanding more about the role of this intriguing gene from different phenotypic perspectives.

scholarly journals Cell adhesion molecule-1 shedding induces apoptosis of renal epithelial cells and exacerbates human nephropathies

2018 ◽  
Vol 314 (3) ◽  
pp. F388-F398 ◽  
Author(s):  
Takashi Kato ◽  
Man Hagiyama ◽  
Yasutoshi Takashima ◽  
Azusa Yoneshige ◽  
Akihiko Ito
Keyword(s):  
Cell Adhesion ◽  
Epithelial Cells ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Molecular Mechanisms ◽  
Immunohistochemical Analysis ◽  
Diagnostic Methods ◽  
Homophilic Binding ◽  
Renal Tubular ◽  
Cell Adhesion Molecule 1

Chronic kidney disease (CKD) is an important problem throughout the world, associated with the increase of blood urea nitrogen (BUN) and serum creatinine (sCre) and with renal tubular injuries. It is crucial to elucidate the molecular mechanisms of renal injuries to identify the new therapeutics and early diagnostic methods. We focused on cell adhesion molecule-1 (CADM1) protein. CADM1, its isoform SP4, is expressed in the epithelial cells of various tissues, including renal distal tubules, localized on the lateral cell membrane, mediates cell-cell adhesion via trans-homophilic binding, and interacts with various proteins. We previously reported that its expression was downregulated by post-proteolytic cleavage (α- and β-shedding) in pulmonary diseases. To investigate whether CADM1 α-shedding occurs in human nephropathies, we performed Western blotting and immunohistochemical analysis of specimens with arterionephrosclerosis (AS) and diabetic nephropathy (DN) from autopsied kidneys. CADM1 α-shedding was induced in AS and DN kidneys and derived from the decrease in full-length CADM1 (FL-CADM1) and increase of the COOH-terminal fragment (α-CTF). In particular, the reduced FL-CADM1 level was correlated with tubular and tubulointerstitial injuries and the increases in BUN and sCre levels. Apoptosis of renal tubular epithelial cells (TECs) was promoted in both nephropathies, and it was significantly correlated with the decrease in the FL-CADM1. Furthermore, FL-CADM1 knockdown by small interfering RNA downregulated anti-apoptotic Bcl-2 protein and promoted apoptosis of cultured renal TECs. The present study suggests that the reduction of FL-CADM1 leads to renal TEC apoptosis and could exacerbate renal tubular and tubulointerstitial injuries, which contribute to the development of CKD.

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