LNPEP
Description
The LNPEP (leucyl and cystinyl aminopeptidase) is a protein-coding gene located on chromosome 5.
LNPEP (Leucyl and cystinyl aminopeptidase) encodes Insulin regulated aminopeptidase (IRAP), a type II transmembrane protein belonging to the oxytocinase subfamily of M1 aminopeptidases. IRAP is found in different cell types, primarily in regulated endosomes that move to the cell surface upon specific receptor activation. Its function varies depending on the cell type and environment. In adipocytes and muscle cells, IRAP is a key component of Glut4storage vesicles (GSV) and controls GSV trafficking in response to insulin receptor signaling. Impaired IRAP recruitment to the cell surface, as seen in type 2 diabetes, disrupts glucose uptake by hindering glucose transporter type 4 (Glut4) trafficking to the cell membrane. This highlights IRAP's crucial role in glucose metabolism. IRAP breaks down various hormones, vasoactive peptides, and neuropeptides, including oxytocin, somatostatin, cholecystokinin, angiotensin III, Lys-bradykinin, arginin vasopressin, Met-and Leu-enkephalin, neurokinin A, and dynorphin A. Many of these peptides are involved in neurological disorders like schizophrenia and memory impairments. IRAP deregulation and its impact on neuropeptide levels are thought to contribute to learning and cognitive problems, emphasizing its importance in memory functions.
LNPEP cleaves amino acids from the N-terminus of peptides, specifically targeting cysteine and leucine residues. It degrades hormones like oxytocin, vasopressin, and angiotensin III, contributing to pregnancy homeostasis. LNPEP might inactivate neuronal peptides in the brain, cleaving Met-enkephalin and dynorphin. It binds to angiotensin IV, potentially acting as its receptor in the brain. (Evidence: PubMed:11389728, PubMed:11707427, PubMed:1731608)
LNPEP is also known as CAP, IRAP, P-LAP, PLAP.
