The p11 subunit of annexin II heterotetramer is regulated by basic carboxypeptidase.
The Ca(2+)-dependent phospholipid-binding protein annexin II heterotetramer (AIIt) is composed of two copies of annexin II and a p11 dimer. The interaction of the carboxyl-terminal lysine residues of the p11 subunit of AIIt with the lysine- binding kringle domains of plasminogen is believed to play a key role in plasminogen binding and stimulation of the tPA-catalyzed cleavage of plasminogen to plasmin. In the current report, we show that AIIt-stimulated plasminogen activation is regulated by basic carboxypeptidases, in vitro. The incubation of AIIt with a 1/400 molar ratio of carboxypeptidase B for periods as short as 2 min resulted in a significant loss in AIIt- stimulated plasminogen activation. Carboxypeptidase B ( CpB) as well as thrombin- activated fibrinolysis inhibitor (TAFIa) and carboxypeptidase N (CpN) rapidly reduced AIIt- stimulated plasminogen activation by 80%. The molar ratio of carboxypeptidase/AIIt for half-maximal inhibition of AIIt was 1/4700, 1/700, and 1/500 for CpB, TAFIa, and CpN, respectively. Treatment of AIIt with carboxypeptidase resulted in loss of both carboxyl-terminal lysine residues from the p11 subunit, which correlated with a decrease in the k(cat) and an increase in the K(m) for plasminogen activation. The data reveal a novel mechanism for the regulation of AIIt-stimulated plasminogen activation.[1]References
- The p11 subunit of annexin II heterotetramer is regulated by basic carboxypeptidase. Fogg, D.K., Bridges, D.E., Cheung, K.K., Kassam, G., Filipenko, N.R., Choi, K.S., Fitzpatrick, S.L., Nesheim, M., Waisman, D.M. Biochemistry (2002) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Useapsburg
