Faculty Collaboration Database

The Role of Sialylated Glycans in Human Platelet Endothelial Cell Adhesion Molecule 1 (PECAM-1)-mediated Trans Homophilic Interactions and Endothelial Cell Barrier Function. J Biol Chem 2016 Dec 09;291(50):26216-26225

Date

10/30/2016

Pubmed ID

27793989

Pubmed Central ID

PMC5207088

DOI

10.1074/jbc.M116.756502

Scopus ID

2-s2.0-85002858868 (requires institutional sign-in at Scopus site)   26 Citations

Abstract

Platelet Endothelial Cell Adhesion Molecule 1 (PECAM-1) is a major component of the endothelial cell intercellular junction. Previous studies have shown that PECAM-1 homophilic interactions, mediated by amino-terminal immunoglobulin homology domain 1, contribute to maintenance of the vascular permeability barrier and to its re-establishment following inflammatory or thrombotic insult. PECAM-1 glycans account for ∼30% of its molecular mass, and the newly solved crystal structure of human PECAM-1 immunoglobulin homology domain 1 reveals that a glycan emanating from the asparagine residue at position 25 (Asn-25) is located within the trans homophilic-binding interface, suggesting a role for an Asn-25-associated glycan in PECAM-1 homophilic interactions. In support of this possibility, unbiased molecular docking studies revealed that negatively charged α2,3 sialic acid moieties bind tightly to a groove within the PECAM-1 homophilic interface in an orientation that favors the formation of an electrostatic bridge with positively charged Lys-89, mutation of which has been shown previously to disrupt PECAM-1-mediated homophilic binding. To verify the contribution of the Asn-25 glycan to endothelial barrier function, we generated an N25Q mutant form of PECAM-1 that is not glycosylated at this position and examined its ability to contribute to vascular integrity in endothelial cell-like REN cells. Confocal microscopy showed that although N25Q PECAM-1 concentrates normally at cell-cell junctions, the ability of this mutant form of PECAM-1 to support re-establishment of a permeability barrier following disruption with thrombin was significantly compromised. Taken together, these data suggest that a sialic acid-containing glycan emanating from Asn-25 reinforces dynamic endothelial cell-cell interactions by stabilizing the PECAM-1 homophilic binding interface.

Author List

Lertkiatmongkol P, Paddock C, Newman DK, Zhu J, Thomas MJ, Newman PJ

Authors

Debra K. Newman PhD Investigator in the Blood Research Institute department at BloodCenter of Wisconsin
Peter J. Newman PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
Debra K. Newman PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
Michael J. Thomas PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
Jieqing Zhu PhD Assistant Professor, Associate Investigator in the Biochemistry department at BloodCenter of Wisconsin

MESH terms used to index this publication - Major topics in bold

Amino Acid Substitution
Cell Communication
Cell Line
Endothelial Cells
Humans
Mutation, Missense
Platelet Endothelial Cell Adhesion Molecule-1
Polysaccharides
Sialic Acids
Thrombin