LNPEP
This gene encodes a zinc-dependent aminopeptidase that cleaves vasopressin, oxytocin, lys-bradykinin, met-enkephalin, dynorphin A and other peptide hormones. The protein can be secreted in maternal serum, reside in intracellular vesicles with the insulin-responsive glucose transporter GLUT4, or form a type II integral membrane glycoprotein. The protein catalyzes the final step in the conversion of angiotensinogen to angiotensin IV (AT4) and is also a receptor for AT4. Alternative splicing results in multiple transcript variants encoding different isoforms.
Full Name
leucyl and cystinyl aminopeptidase
Function
Release of an N-terminal amino acid, cleaves before cysteine, leucine as well as other amino acids. Degrades peptide hormones such as oxytocin, vasopressin and angiotensin III, and plays a role in maintaining homeostasis during pregnancy. May be involved in the inactivation of neuronal peptides in the brain. Cleaves Met-enkephalin and dynorphin. Binds angiotensin IV and may be the angiotensin IV receptor in the brain.
Biological Process
Antigen processing and presentation of exogenous peptide antigen via MHC class I, TAP-independentTAS:Reactome
Cell-cell signalingManual Assertion Based On ExperimentTAS:ProtInc
Female pregnancyManual Assertion Based On ExperimentTAS:ProtInc
Negative regulation of cold-induced thermogenesisBy SimilarityISS:YuBioLab
Peptide catabolic processManual Assertion Based On ExperimentIBA:GO_Central
Protein catabolic processIEA:Ensembl
Protein polyubiquitinationTAS:Reactome
ProteolysisManual Assertion Based On ExperimentIBA:GO_Central
Regulation of blood pressureManual Assertion Based On ExperimentIBA:GO_Central
Signal transductionManual Assertion Based On ExperimentIBA:GO_Central
SMAD protein signal transductionIEA:Ensembl
Cellular Location
Cell membrane
In brain only the membrane-bound form is found. The protein resides in intracellular vesicles together with GLUT4 and can then translocate to the cell surface in response to insulin and/or oxytocin. Localization may be determined by dileucine internalization motifs, and/or by interaction with tankyrases.
Leucyl-cystinyl aminopeptidase, pregnancy serum form
Secreted
During pregnancy serum levels are low in the first trimester, rise progressively during the second and third trimester and decrease rapidly after parturition.
Topology
Cytoplasmic: 1-110
Helical: 111-131
Extracellular: 132-1025
PTM
The pregnancy serum form is derived from the membrane-bound form by proteolytic processing.
N-glycosylated.