Transmembrane protein 30A (TMEM30A)

Transmembrane protein 30A (TMEM30A), also known as CDC50A, is a type II transmembrane protein that serves as an essential beta-subunit for P4-ATPases, which are enzymes responsible for maintaining phospholipid asymmetry in the plasma membrane by flipping lipids from the outer to the inner leaflet (UniProt Q9NV96). In the field of drug delivery, TMEM30A has been identified as the primary receptor for the llama-derived single-domain antibody FC5, which crosses the blood-brain barrier (BBB) via receptor-mediated transcytosis (RMT) (PubMed: 26453548). Upon binding to TMEM30A on the luminal surface of brain microvascular endothelial cells, the receptor-ligand complex is internalized into clathrin-coated vesicles and transported across the cell to the brain parenchyma (PubMed: 30103369). This mechanism makes TMEM30A a highly attractive therapeutic target for the delivery of CNS-active drugs, including peptides and antibodies, that otherwise cannot penetrate the BBB. Research suggests that utilizing TMEM30A as a shuttle does not significantly interfere with its native biological role in lipid transport, providing a relatively safe window for pharmacological intervention in neurodegenerative diseases and brain tumors (PubMed: 26453548).

Other names

CDC50ACell cycle control protein 50AP4-ATPase flippase complex beta subunit TMEM30AC6orf67CDC50 cell cycle control protein-like 1

Facilitates receptor-mediated transcytosis (RMT) across the blood-brain barrier by binding specific ligands (like the FC5 antibody) and triggering endocytic transport from the luminal to the abluminal surface of brain endothelial cells.