γ-Secretase and presenilin mediate cleavage and phosphorylation of vascular endothelial growth factor receptor-1.
We have reported previously that pigment epithelium-derived factor (PEDF) can, via γ-secretase-mediated events, inhibit VEGF-induced angiogenesis in microvascular endothelial cells by both (a) cleavage and intracellular translocation of a C-terminal fragment of VEGF receptor-1 (VEGFR1) and (b) inhibition of VEGF-induced phosphorylation of VEGFR1. Using site-direct mutagenesis and transfection of wild type and mutated receptors into endothelial cells, we showed that transmembrane cleavage of VEGFR1 occurs at valine 767 and that a switch from valine to alanine at this position prevented cleavage and formation of a VEGFR1 intracellular fragment. Using siRNA to selectively knock down protein-tyrosine phosphatases (PTPs) in endothelial cells, we demonstrated that vascular endothelial PTP is responsible for dephosphorylation of activated VEGFR1. PEDF up-regulation of full-length presenilin 1 (Fl.PS1) facilitated the association of vascular endothelial PTP and VEGFR1. Knockdown of Fl.PS1 prevented dephosphorylation of VEGFR1, whereas up-regulation of Fl.PS1 stimulated VEGFR1 dephosphorylation. Fl.PS1 associated with VEGFR1 within 15 min after PEDF treatment. In conclusion, we determined the PEDF-mediated events responsible for VEGFR1 signaling and identified full-length presenilin as a critical adaptor molecule in the dephosphorylation of VEGFR1. This greater understanding of the regulation of VEGFR1 signaling will help identify novel anti-VEGF therapeutic strategies.
Departments of Anatomy and Cell Biology, University of Florida, Gainesville, Florida 32610-0235.
Jun
J
Cai
Departments of Anatomy and Cell Biology, University of Florida, Gainesville, Florida 32610-0235.
Zhijuan
Z
Chen
Departments of Anatomy and Cell Biology, University of Florida, Gainesville, Florida 32610-0235.
Qing
Q
Ruan
Department of Surgery, University of Florida, Gainesville, Florida 32610-0235.
Song
S
Han
Departments of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida 32610-0235.
Li
L
Liu
Departments of Anatomy and Cell Biology, University of Florida, Gainesville, Florida 32610-0235.
Xiaoping
X
Qi
Department of Ophthalmology, University of Florida, Gainesville, Florida 32610-0235.
Sanford L
SL
Boye
Department of Ophthalmology, University of Florida, Gainesville, Florida 32610-0235.
William W
WW
Hauswirth
Departments of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida 32610-0235.
Maria B
MB
Grant
Departments of Anatomy and Cell Biology, University of Florida, Gainesville, Florida 32610-0235. Electronic address: meboulton@ufl.edu.
Michael E
ME
Boulton
D000409:Alanine / Q000737:chemistry; D000595:Amino Acid Sequence; D053829:Amyloid Precursor Protein Secretases / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D005136:Eye Proteins / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008833:Microcirculation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009389:Neovascularization, Pathologic; D009414:Nerve Growth Factors / Q000378:metabolism; D010766:Phosphorylation; D053764:Presenilin-1 / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D012160:Retina / Q000378:metabolism; D015843:Serpins / Q000378:metabolism; D014633:Valine / Q000737:chemistry; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000378:metabolism*; D000099174:Pigment Epithelium-Derived Factor
D000409:Alanine; D053829:Amyloid Precursor Protein Secretases; D005136:Eye Proteins; D036341:Intercellular Signaling Peptides and Proteins; D009414:Nerve Growth Factors; D053764:Presenilin-1; D017027:Protein Tyrosine Phosphatases; D034741:RNA, Small Interfering; D015843:Serpins; D014633:Valine; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D000099174:Pigment Epithelium-Derived Factor