title: Selective Targeting of a Novel Epsin-VEGFR2 Interaction Promotes VEGF-Mediated Angiogenesis.
abstract: BACKGROUND
  We previously reported that vascular endothelial growth factor (VEGF)-induced binding of VEGF receptor 2 (VEGFR2) to epsins 1 and 2 triggers VEGFR2 degradation and attenuates VEGF signaling. The epsin ubiquitin interacting motif (UIM) was shown to be required for the interaction with VEGFR2. However, the molecular determinants that govern how epsin specifically interacts with and regulates VEGFR2 were unknown.
  
  
  OBJECTIVE
  The goals for the present study were as follows: (1) to identify critical molecular determinants that drive the specificity of the epsin and VEGFR2 interaction and (2) to ascertain whether such determinants were critical for physiological angiogenesis in vivo.
  
  
  RESULTS
  Structural modeling uncovered 2 novel binding surfaces within VEGFR2 that mediate specific interactions with epsin UIM. Three glutamic acid residues in epsin UIM were found to interact with residues in VEGFR2. Furthermore, we found that the VEGF-induced VEGFR2-epsin interaction promoted casitas B-lineage lymphoma-mediated ubiquitination of epsin, and uncovered a previously unappreciated ubiquitin-binding surface within VEGFR2. Mutational analysis revealed that the VEGFR2-epsin interaction is supported by VEGFR2 interacting specifically with the UIM and with ubiquitinated epsin. An epsin UIM peptide, but not a mutant UIM peptide, potentiated endothelial cell proliferation, migration and angiogenic properties in vitro, increased postnatal retinal angiogenesis, and enhanced VEGF-induced physiological angiogenesis and wound healing.
  
  
  CONCLUSIONS
  Distinct residues in the epsin UIM and VEGFR2 mediate specific interactions between epsin and VEGFR2, in addition to UIM recognition of ubiquitin moieties on VEGFR2. These novel interactions are critical for pathophysiological angiogenesis, suggesting that these sites could be selectively targeted by therapeutics to modulate angiogenesis.
authors.affiliation: Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: H N Ashiqur
authors.initials: HNA
authors.lastname: Rahman
authors.affiliation: Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
authors.affiliation: Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: Yunzhou
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA.
authors.forename: Satish
authors.initials: S
authors.lastname: Pasula
authors.affiliation: Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: Aiyun
authors.initials: A
authors.lastname: Wen
authors.affiliation: Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: Ye
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.|Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, Oklahoma, OK 73104, USA.
authors.forename: Megan L
authors.initials: ML
authors.lastname: Brophy
authors.affiliation: Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA.
authors.forename: Kandice L
authors.initials: KL
authors.lastname: Tessneer
authors.affiliation: Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Cai
authors.affiliation: Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA.
authors.forename: John
authors.initials: J
authors.lastname: McManus
authors.affiliation: Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA.
authors.forename: Baojun
authors.initials: B
authors.lastname: Chang
authors.affiliation: Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: Sukyoung
authors.initials: S
authors.lastname: Kwak
authors.affiliation: Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA.
authors.forename: Negar S
authors.initials: NS
authors.lastname: Rahman
authors.affiliation: Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA.
authors.forename: Wenjia
authors.initials: W
authors.lastname: Xu
authors.affiliation: Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA.
authors.forename: Conrad
authors.initials: C
authors.lastname: Fernandes
authors.affiliation: Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA.
authors.forename: John Michael
authors.initials: JM
authors.lastname: Mcdaniel
authors.affiliation: Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA.
authors.forename: Lijun
authors.initials: L
authors.lastname: Xia
authors.affiliation: Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: Lois
authors.initials: L
authors.lastname: Smith
authors.affiliation: Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA.
authors.forename: R Sathish
authors.initials: RS
authors.lastname: Srinivasan
authors.affiliation: Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D016503:Drug Delivery Systems / Q000639:trends; D057809:HEK293 Cells; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D061986:MCF-7 Cells; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D018919:Neovascularization, Physiologic / Q000502:physiology*; D011485:Protein Binding / Q000502:physiology; D017433:Protein Structure, Secondary; D042461:Vascular Endothelial Growth Factor A / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C114154:epsin; C000588866:KDR protein, human; D040301:Vascular Endothelial Growth Factor Receptor-2
keywords: VEGFR2 protein, mouse; epsin; neovascularization, physiologic; ubiquitin; ubiquitination