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  3. Elucidating the molecular basis of PECAM-1 and Tie2 interaction from binding dynamics and complex formation

Elucidating the molecular basis of PECAM-1 and Tie2 interaction from binding dynamics and complex formation

  • Biochem Biophys Res Commun. 2024 Jul 31:735:150484. doi: 10.1016/j.bbrc.2024.150484.
Hao Li 1,  Rui Wang 1,  Peng Xu 2,  Cai Yuan 2,  Mingdong Huang 3,  Longguang Jiang 4
Affiliations

Affiliations

  • 1 College of Chemistry, Fuzhou University, Fuzhou, 350116, China.
  • 2 College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350116, China.
  • 3 College of Chemistry, Fuzhou University, Fuzhou, 350116, China; The National & Local Joint Engineering Research Center on Biopharmaceutical and Photodynamic Therapy Technologies, Fuzhou University, Fuzhou, Fujian, 350116, China. Electronic address: hmd_lab@fzu.edu.cn.
  • 4 College of Chemistry, Fuzhou University, Fuzhou, 350116, China; The National & Local Joint Engineering Research Center on Biopharmaceutical and Photodynamic Therapy Technologies, Fuzhou University, Fuzhou, Fujian, 350116, China. Electronic address: jianglg@fzu.edu.cn.
PMID: 39094232 DOI: 10.1016/j.bbrc.2024.150484
Abstract

Background: Endothelial hyperpermeability-induced vascular dysfunction is a prevalent and significant characteristic in critical illnesses such as sepsis and Other conditions marked by acute systemic inflammation. Platelet endothelial cell adhesion molecule-1 (PECAM-1) and Tie2 serve as transmembrane receptors within endothelial cells (ECs), playing pivotal roles not only in maintaining EC-EC junctions but also in influencing vasculogenesis, vessel homeostasis, and vascular remodeling.

Objectives: At present, the molecular basis of the PECAM-1-Tie2 interaction remains inadequately elucidated. In the study, recombinant soluble PECAM-1 (sPECAM-1) and Tie2 (sTie2) were expressed by Drosophila S2 and HEK293 expression systems, respectively. The interactions between sPECAM-1 and sTie2 were investigated using the Surface Plasmon Resonance (SPR) and size-exclusion chromatography methods. An immunofluorescence assay was used to detect the binding of sPECAM-1 and sTie2 on endothelial cells.

Results: PECAM-1 was found to bind with sTie2 in a sodium and pH-dependent manner as confirmed by the ELISA, the D5-D6 domains of PECAM-1 might play a crucial role in binding with sTie2. Surface Plasmon Resonance (SPR) results showed that the full length of sPECAM-1 has the strongest binding affinity (KD = 48.4 nM) with sTie2, compared to sPECAM-1-D1-D4 and sPECAM-1-D1-D2. This result is consistent with that in the ELISA. In addition, size-exclusion chromatography demonstrated that sPECAM-1, sTie2, and Ang1 can form a ternary complex.

Conclusion: In this study, we determined that sPECAM-1 binds to sTie2 in a pH and sodium-dependent manner. The full length of sPECAM-1 has the strongest binding affinity, and the D5-D6 domains in sPECAM-1 play a crucial role in the interaction between sPECAM-1 and sTie2.

Keywords

Angiopoietin-1; Endothelial cell; PECAM-1; Protein-protein interaction; Tie2.

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