Lyve-1, soluble

A DNA sequence encoding the extracellular domain of mouse LYVE-1 (Met1 – Gly228) was fused to a C-terminal His-tag (6xHis) and expressed in insect cells. Based on N-terminal sequence analysis, the primary structure of recombinant mature sLYVE-1 starts at Ala24. sLYVE-1 has a calculated monomeric molecular mass of about 25 kDa but as a result of glycosylation, migrates at approximately 35 - 45 kDa under reducing conditions in SDS-PAGE. LYVE-1 has been identified as a major receptor for HA (extracellular matrix glycosaminoglycan hyaluronan) on the lymph vessel wall. The deduced amino acid sequence of LYVE-1 predicts a 322-residue type I integral membrane polypeptide 41% similar to the CD44 HA receptor with a 212-residue extracellular domain containing a single Link module the prototypic HA binding domain of the Link protein superfamily. Like CD44, the LYVE-1 molecule binds both soluble and immobilized HA. However, unlike CD44, the LYVE-1 molecule colocalizes with HA on the luminal face of the lymph vessel wall and is completely absent from blood vessels. Hence, LYVE-1 is the first lymph-specific HA receptor to be characterized and is a uniquely powerful marker for lymph vessels themselves.