Collectrin (TMEM27)

Collectrin (TMEM27) is a type I transmembrane glycoprotein and a non-catalytic homolog of angiotensin-converting enzyme 2 (ACE2) (1.2.1, 1.3.4). It is primarily expressed in the renal proximal tubules and pancreatic beta cells (1.2.4, 2.2.3). In the kidney, it acts as a vital chaperone for the trafficking of neutral amino acid transporters (such as SLC6A19/B0AT1) to the apical membrane; its deficiency leads to severe aminoaciduria and salt-sensitive hypertension (1.2.1, 1.2.3, 1.4.1). In the pancreas, collectrin regulates insulin exocytosis by interacting with the SNARE complex and promotes beta-cell proliferation (1.1.2, 1.2.1, 2.4.4). Due to its dual role in metabolic and cardiovascular homeostasis, it is being investigated as a therapeutic target for hypertension and diabetes, particularly through the use of BACE2 inhibitors that prevent its shedding from the cell surface (2.3.3, 2.4.1, 2.4.3). Additionally, urinary collectrin has emerged as a unique biomarker for acute kidney injury, where its levels decrease, unlike most other renal injury markers (1.2.2, 1.4.2).

Other names

Transmembrane protein 27CLTRNNX17NX-17Kidney-specific membrane proteinAmino acid transport regulator

Collectrin acts as a chaperone for neutral amino acid transporters (e.g., SLC6A19) to the apical membrane of renal tubules. In pancreatic beta cells, it facilitates SNARE complex formation for insulin exocytosis and promotes cell proliferation. BACE2 inhibitors prevent the proteolytic shedding of Collectrin, thereby increasing its surface expression and enhancing beta-cell function.