Tissue plasminogen activator is a ligand of cation-independent mannose 6-phosphate receptor and consists of glycoforms that contain mannose 6-phosphate. Sci Rep 2021 Apr 15;11(1):8213
Date
04/17/2021Pubmed ID
33859256Pubmed Central ID
PMC8050316DOI
10.1038/s41598-021-87579-zScopus ID
2-s2.0-85104287178 (requires institutional sign-in at Scopus site) 2 CitationsAbstract
Plasmin is the key enzyme in fibrinolysis. Upon interaction with plasminogen activators, the zymogen plasminogen is converted to active plasmin. Some studies indicate plasminogen activation is regulated by cation-independent mannose 6-phosphate receptor (CI-MPR), a protein that facilitates lysosomal enzyme trafficking and insulin-like growth factor 2 downregulation. Plasminogen regulation may be accomplished by CI-MPR binding to plasminogen or urokinase plasminogen activator receptor. We asked whether other members of the plasminogen activation system, such as tissue plasminogen activator (tPA), also interact with CI-MPR. Because tPA is a glycoprotein with three N-linked glycosylation sites, we hypothesized that tPA contains mannose 6-phosphate (M6P) and binds CI-MPR in a M6P-dependent manner. Using surface plasmon resonance, we found that two sources of tPA bound the extracellular region of human and bovine CI-MPR with low-mid nanomolar affinities. Binding was partially inhibited with phosphatase treatment or M6P. Subsequent studies revealed that the five N-terminal domains of CI-MPR were sufficient for tPA binding, and this interaction was also partially mediated by M6P. The three glycosylation sites of tPA were analyzed by mass spectrometry, and glycoforms containing M6P and M6P-N-acetylglucosamine were identified at position N448 of tPA. In summary, we found that tPA contains M6P and is a CI-MPR ligand.
Author List
Miller JJ, Bohnsack RN, Olson LJ, Ishihara M, Aoki K, Tiemeyer M, Dahms NMAuthors
Kazuhiro Aoki PhD Associate Professor in the Cell Biology, Neurobiology and Anatomy department at Medical College of WisconsinRichard N. Bohnsack Research Scientist I in the Biochemistry department at Medical College of Wisconsin
Nancy M. Dahms PhD Professor in the Biochemistry department at Medical College of Wisconsin
Linda J. Olson PhD Assistant Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AcetylglucosamineAnimals
CHO Cells
Cells, Cultured
Cricetulus
Glycoproteins
Humans
Insulin-Like Growth Factor II
Ligands
Mannosephosphates
Phosphorylation
Protein Binding
Protein Interaction Domains and Motifs
Receptor, IGF Type 2
Sf9 Cells
Spodoptera
Tissue Plasminogen Activator