A novel type of binding specificity to phospholipids for rat mannose-binding proteins isolated from serum and liver.
Mannose-binding protein (MBP) belongs to the collectin subgroup of C-type lectins with specificity for mannose and N-acetylglucosamine sugars. We investigated whether rat MBPs isolated from serum (S-MBP) and liver (L-MBP) interact with phospholipids using antibody against each MBP. Both S- and L-MBPs bound to phosphatidylinositol coated onto microtiter wells in a concentration- and a Ca2+-dependent manner. L-MBP also bound to phosphatidylglycerol and weakly to phosphatidylserine. MBPs interacted with liposomes composed of these lipids. S- and L-MBPs bound to phosphatidylinositol 4-monophosphate. L-MBP also bound to cardiolipin. These results provide evidence for a novel type of ligand binding specificity for MBPs, and raise the possibility that phospholipids are ligands for collectins.
Kuroki
Y
Y
Department of Biochemistry, Sapporo Medical University School of Medicine, Japan. kurokiy@serpent.cc.sapmed.ac.jp
Honma
T
T
Chiba
H
H
Sano
H
H
Saitoh
M
M
Ogasawara
Y
Y
Sohma
H
H
Akino
T
T
D000209:Acute-Phase Proteins / Q000378:metabolism*; D000818:Animals; D000906:Antibodies; D001665:Binding Sites; D001667:Binding, Competitive; D002118:Calcium / Q000494:pharmacology; D002241:Carbohydrates / Q000494:pharmacology; D002352:Carrier Proteins / Q000097:blood / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D037241:Mannose-Binding Lectins; D010713:Phosphatidylcholines / Q000378:metabolism; D010715:Phosphatidylglycerols / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010718:Phosphatidylserines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000209:Acute-Phase Proteins; D000906:Antibodies; D002241:Carbohydrates; D002352:Carrier Proteins; D037241:Mannose-Binding Lectins; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D010716:Phosphatidylinositols; D010718:Phosphatidylserines; D010743:Phospholipids; D002118:Calcium