Protein kinase C regulates FLT1 abundance and stimulates its cleavage in vascular endothelial cells with the release of a soluble PlGF/VEGF antagonist

Nandita S Raikwar; Kang Z Liu; Christie P Thomas

doi:10.1016/j.yexcr.2013.07.005

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Protein kinase C regulates FLT1 abundance and stimulates its cleavage in vascular endothelial cells with the release of a soluble PlGF/VEGF antagonist

Journal article

Peer reviewed

Protein kinase C regulates FLT1 abundance and stimulates its cleavage in vascular endothelial cells with the release of a soluble PlGF/VEGF antagonist

Nandita S Raikwar, Kang Z Liu and Christie P Thomas

Experimental cell research, Vol.319(17), pp.2578-2587

10/15/2013

DOI: 10.1016/j.yexcr.2013.07.005

PMCID: PMC3797157

PMID: 23911939

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Abstract

FLT1 and its soluble form (sFLT1) arise as alternate transcripts from the same gene and sFLT1 can antagonize the effect of vascular endothelial growth factor (VEGF) on its cognate receptors. We investigated the effect of VEGF and protein kinase C (PKC) activation on sFLT1 abundance. We demonstrated that VEGF stimulates sFLT1 and FLT1 mRNA and protein levels in vascular endothelial cells via VEGFR2 and PKC. Using an FLT1 expression vector with N and C-terminal epitope tags, we show that PKC activation increases the cleavage of FLT1 into an N-terminal extracellular fragment and a C-terminal intracellular fragment with the cleavage occurring adjacent to the transmembrane domain. The trafficking and glycosylation inhibitors brefeldin, monensin and tunicamycin substantially reduced cleavage and release of the N-terminal ectodomain of FLT1 and inhibited secretion of the isoforms of sFLT1. The shed FLT1 ectodomain can bind VEGF and PlGF and inhibit VEGF-induced vascular tube formation thus confirming that it is functionally equivalent to the alternately spliced and secreted sFLT1 isoforms. •We investigated the effect of VEGF and PKC activation on sFLT1 and Flt1 expression.•We demonstrate that VEGF stimulates sFLT1 and FLT1 in vascular endothelial cells via VEGFR2 and PKC.•We show that PKC activation stimulates the cleavage of FLT1 into an N-terminal ectodomain and a C-terminal intracellular fragment.•The shed FLT1 ectodomain can bind PlGF and VEGF and inhibit VEGF-induced vasculogenesis.•The study confirms that the Flt1 ectodomain is functionally equivalent to the alternately transcribed and secreted sFLT1 isoforms.

Angiogenesis

Soluble receptor

Proteolytic cleavage

Details

Title: Subtitle: Protein kinase C regulates FLT1 abundance and stimulates its cleavage in vascular endothelial cells with the release of a soluble PlGF/VEGF antagonist
Creators: Nandita S Raikwar - Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, IA, USA
Kang Z Liu - Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, IA, USA
Christie P Thomas - Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, IA, USA
Resource Type: Journal article
Publication Details: Experimental cell research, Vol.319(17), pp.2578-2587
DOI: 10.1016/j.yexcr.2013.07.005
PMID: 23911939
PMCID: PMC3797157
NLM abbreviation: Exp Cell Res
ISSN: 0014-4827
eISSN: 1090-2422
Publisher: Elsevier Inc
Grant note: name: New Directions Grant from the American Society of Nephrology; name: VA Merit Review Award; DOI: 10.13039/100000002, name: National Institutes of Health, award: RO1 DK090053
Language: English
Date published: 10/15/2013
Academic Unit: Stead Family Department of Pediatrics; Obstetrics and Gynecology; Internal Medicine
Record Identifier: 9983986081902771

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