meprin A complex

Definition

Target type: cellularcomponent

A protein complex that is located in the cell membrane, and is involved in the metabolism of peptides, including neuropeptides. The complex has metalloendopeptidase activity that catalyzes the hydrolysis of protein and peptide substrates, preferentially on carboxyl side of hydrophobic residues. [GOC:mah, MEROPS_fam:M12]

Meprin A is a metalloproteinase that forms a complex with the meprin B subunit. The complex is found in the plasma membrane of various cell types, particularly in the gastrointestinal tract and kidney. The meprin A complex is composed of two distinct subunits:

**Meprin A subunit:** This subunit is a type I transmembrane protein. It contains a large extracellular domain that possesses the catalytic activity. The extracellular domain includes:
- **A propeptide domain:** This domain is cleaved during activation of the enzyme.
- **A catalytic domain:** This domain is responsible for the proteolytic activity of the enzyme. It contains the zinc-binding site that is essential for catalysis.
- **A hemopexin-like domain:** This domain is involved in substrate binding and regulation of enzyme activity.

**Meprin B subunit:** This subunit is a type II transmembrane protein. It is non-catalytic and serves as a regulatory subunit. The extracellular domain of the meprin B subunit contains a region that binds to the meprin A subunit, forming the heterodimer.

The meprin A complex localizes to the plasma membrane, specifically to **lipid rafts**, which are specialized membrane microdomains enriched in cholesterol and sphingolipids. Localization to these rafts is crucial for its function and interaction with other proteins. The meprin A complex is also found in **exosomes**, small vesicles that are released from cells and participate in intercellular communication.

Overall, the meprin A complex is a multimeric protein complex that plays a crucial role in various physiological processes. Its localization within the cell membrane and in exosomes highlights its importance in cell signaling and communication.'
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Proteins (1)

Compounds (2)