What is the structure of Chimeric antigen receptor (CAR)?

Chimeric antigen receptors (CARs) consist of four main parts: an antigen recognition domain, a transmembrane domain, a hinge region (together referred to as the ectodomain), and an intracellular T cell signaling domain (also known as the endodomain). The endodomain represents the intracellular tail of the CAR and is essential for signaling within the T cell. It commonly includes components like the CD3ζ chain, which contains immunoreceptor tyrosine-based activation motifs (ITAMs). The transmembrane domain consists of a hydrophobic alpha helix that spans the lipid bilayer. This domain is crucial for anchoring the CAR protein in the cell membrane and ensuring its stability. The ectodomain is the part of the protein located outside the cell, exposed to the extracellular environment. It consists of a signal peptide, a spacer region that connects the antigen binding domain to the transmembrane domain, and an antigen recognition region.