MMRN1
Function
Carrier protein for platelet (but not plasma) factor V/Va. Plays a role in the storage and stabilization of factor V in platelets. Upon release following platelet activation, may limit platelet and plasma factor Va-dependent thrombin generation. Ligand for integrin alpha-IIb/beta-3 and integrin alpha-V/beta-3 on activated platelets, and may function as an extracellular matrix or adhesive protein.
Involvement in disease
Deficiency in multimerin-1 due to proteolytic degradation within the platelet alpha granules is associated with an autosomal dominant bleeding disorder (factor V Quebec).
Post-translational modifications
The N-terminus is blocked.
Extensively N-glycosylated.
Tissue Specificity
Synthesized by endothelial cells and megakaryocytes. Stored in platelet alpha granules and endothelial cell Weibel-Palade bodies, following activation of these cells, it is released and attached to megakaryocytes, platelets, endothelium and subendothelium of blood vessels. Not found in plasma. Found in vascular tissues such as placenta, lung, and liver.
Cellular localization
- Secreted
- O-fucosylation of Thr-216 and Thr-1055 is important for protein secretion.
Alternative names
ECM, EMILIN4, GPIA*, MMRN, MMRN1, Multimerin-1, EMILIN-4, Elastin microfibril interface located protein 4, Endothelial cell multimerin, Elastin microfibril interfacer 4