Journal article
VEGF-A selectively inhibits FLT1 ectodomain shedding independent of receptor activation and receptor endocytosis
American Journal of Physiology - Cell Physiology, Vol.315(2), pp.C214-C224
08/01/2018
DOI: 10.1152/ajpcell.00247.2017
PMCID: PMC6139503
PMID: 29719170
Abstract
Ectodomain shedding and regulated intracellular proteolysis can determine the fate or function of cell surface proteins. Fms-related tyrosine kinase (FLT) or VEGF receptor 1 is a high-affinity cell surface VEGF-A receptor tyrosine kinase that is constitutively cleaved to release an NH
2
-terminal VEGF-A binding ectodomain that, once shed, can antagonize the effects of VEGF-A in the extracellular milieu. We evaluated the effect of VEGF-A on FLT1 cleavage in native cells and in transient and stable expression systems. We demonstrate that VEGF-A inhibits FLT1 ectodomain cleavage in a time- and dose-dependent manner, whereas VEGF-A knockdown in HEK293 cells increases ectodomain shedding. Although kinase insert domain receptor (KDR) or VEGF receptor 2, analogous to FLT1, is also subject to extracellular and intracellular cleavage, VEGF-A does not inhibit KDR cleavage. VEGF-A inhibition of FLT1 cleavage is not dependent on FLT1 tyrosine kinase activity or the intracellular FLT1 residues. N-acetylleucylleucylnorleucinal (ALLN), a proteasomal inhibitor; bafilomycin A, an inhibitor of endosomal acidification; and dynasore, a dynamin inhibitor, all increase the abundance of FLT1 and the shed ectodomain, indicating that FLT1 is subject to dynamin-mediated endocytosis and susceptible to proteasomal and lysosomal degradation. VEGF-A inhibition of cleavage is not reversed by ALLN, bafilomycin A, or dynasore. However, a 30 AA deletion in the extracellular immunoglobulin 7 domain leads to enhanced cleavage of Flt1 with a significant reduction of the VEGF inhibitory effect. Our results indicate that the inhibition of FLT1 ectodomain cleavage by VEGF-A is dependent neither on receptor activation nor on internalization nor a consequence of receptor degradation and likely represents a direct inhibitory effect on receptor cleavage.
Details
- Title: Subtitle
- VEGF-A selectively inhibits FLT1 ectodomain shedding independent of receptor activation and receptor endocytosis
- Creators
- Nandita S Raikwar - University of Iowa Carver College of MedicineMasabumi Shibuya - Institute of Physiology and Medicine, Jobu University, Takasaki, GunmaChristie P Thomas - Veterans Affairs Medical Center
- Resource Type
- Journal article
- Publication Details
- American Journal of Physiology - Cell Physiology, Vol.315(2), pp.C214-C224
- Publisher
- American Physiological Society; Bethesda, MD
- DOI
- 10.1152/ajpcell.00247.2017
- PMID
- 29719170
- PMCID
- PMC6139503
- ISSN
- 0363-6143
- eISSN
- 1522-1563
- Grant note
- RO1 DK090053 / ; ;
- Alternative title
- VEGF-A INHIBITS FLT1 ECTODOMAIN SHEDDING
- Language
- English
- Date published
- 08/01/2018
- Academic Unit
- Stead Family Department of Pediatrics; Obstetrics and Gynecology; Internal Medicine
- Record Identifier
- 9983986082402771
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