Implications of Raftlin in different diseases: from molecular biology to diagnostic value.

Raftlin (raft-linking) protein is an essential component of the lipid raft structure and plays a crucial role in B and T cell signaling pathways. It facilitates B cell receptor (BCR) signaling by promoting calcium mobilization and tyrosine phosphorylation in the cells while colocalizing with BCR on the cell membrane. Interestingly, Raftlin is internalized in lipopolysaccharide-stimulated T cells by colocalization with Toll-like receptor 4 (TLR4), wherein it exerts a similar role as in B cells. The protein also effectuates poly(I:C) internalization into TLR3-positive endosomes in dendritic and epithelial cells through clathrin binding, thereby affecting interferon-β production. In addition, Raftlin controls the vascular endothelial cells and participates in cell growth and proliferation. Recent studies have indicated Raftlin to be a novel biomarker for the diagnosis due to its upregulated expression in malignant diseases. In this integrated study, we present the biological functions of Raftlin and its expression to provide a theoretical basis for the prevention, diagnosis, and treatment of various diseases.