Oligomerization and Multimerization Are Critical for Angiopoietin-1 to Bind and Phosphorylate Tie2

Kyung-Tae Kim, Han-Ho Choi, Michel O. Steinmetz, Bohumil Maco, Richard A. Kammerer, So Young Ahn, Hak-Zoo Kim, Gyun Min Lee, Gou Young Koh
2005 Journal of Biological Chemistry  
Angiopoietin-1 (Ang1) is an essential molecule for blood vessel formation; however, little is known about the structure-function relationships of Ang1 with its receptor, Tie2 (tyrosine kinase with immunoglobulin and epidermal growth factor homology domain-2). In this study, we generated several Ang1 and angiopoietin-2 (Ang2) variants to define the role of the superclustering and oligomerization domains of the Ang1 protein. Then we analyzed the molecular structure of the variants with SDS-PAGE
more » ... nts with SDS-PAGE and rotary metal-shadowing transmission electron microscopy (RMSTEM) and determined the effects of these variants on the binding and activation of Tie2. Ang1 exists as heterogeneous multimers with basic trimeric, tetrameric, and pentameric oligomers, whereas Ang2 exists as trimeric, tetrameric, and pentameric oligomers. The variant Ang1C265S, consisting of trimers, tetramers, and pentamers without . 1 The abbreviations used are: Ang1, angiopoietin-1; Ang2, angiopoi-etin-2; HEK293, human embryonic kidney 293; HUVECs, human umbilical vein endothelial cells; RMSTEM, rotary metal-shadowing transmission electron microscopy; TEM, transmission electron microscopy; Tie2, tyrosine kinase with immunoglobulin and epidermal growth factor homology domain-2.
doi:10.1074/jbc.m500292200 pmid:15769741 fatcat:ov2pw7jbmzfxpiqoyeqaxehzvq