F11r, also known as Junctional Adhesion Molecule -A (JAM -A), is a transmembrane protein belonging to the immunoglobulin superfamily of cell adhesion molecules. It is present in epithelial, endothelial cells, leukocytes, and platelets. In epithelial and endothelial cells, it participates in tight junction formation, maintaining cellular layer integrity by forming homodimers. In leukocytes, it is involved in their transmigration through the vascular wall. It also regulates various biological processes such as paracellular permeability, angiogenesis, and epithelial-to-mesenchymal transition [1,2].

Genetically engineered mice lacking F11r in platelets were created to study its role. These platelets were abnormally reactive, indicating that F11r in platelets acts as a negative regulator of a key mechanism triggering platelet aggregation [1]. In pancreatic cancer cells, knockdown of F11r led to decreased cell proliferation, loss of invasiveness, cell cycle arrest in G1 phase, and enhanced apoptosis, suggesting it may be a promising therapeutic target for pancreatic cancer [3].

In conclusion, F11r is crucial for maintaining normal cellular functions, especially in processes related to cell adhesion and migration. The use of gene-knockout mouse models has revealed its role in platelet reactivity and in cancer-related processes such as pancreatic cancer cell malignancy. Understanding F11r's functions can provide new insights into hemostasis, thrombosis, and cancer treatment strategies.

References:

1. Kamola, Piotr, Babinska, Anna, Przygodzki, Tomasz. . F11R/JAM-A: why do platelets express a molecule which is also present in tight junctions? In Platelets, 34, 2214618. doi:10.1080/09537104.2023.2214618. https://pubmed.ncbi.nlm.nih.gov/37246517/

2. Czubak-Prowizor, Kamila, Babinska, Anna, Swiatkowska, Maria. 2021. The F11 Receptor (F11R)/Junctional Adhesion Molecule-A (JAM-A) (F11R/JAM-A) in cancer progression. In Molecular and cellular biochemistry, 477, 79-98. doi:10.1007/s11010-021-04259-2. https://pubmed.ncbi.nlm.nih.gov/34533648/

3. Zhang, HaiDi, Zhang, RenDan, Yao, Jiaxin, Mu, Bo, Zhao, ChunYan. 2022. Effect of F11R Gene Knockdown on Malignant Biological Behaviors of Pancreatic Cancer Cells. In Journal of oncology, 2022, 3379027. doi:10.1155/2022/3379027. https://pubmed.ncbi.nlm.nih.gov/35295710/