CLEC14a-HSP70-1A interaction regulates HSP70-1A-induced angiogenesis

Jihye Jang,Sukmook Lee,Mi Ra Kim,Jong Heon Kim,Kyun Heo,Taek-Keun Kim,Woo Ran Lee

doi:10.1038/s41598-017-11118-y

Jihye Jang, Sukmook Lee + Show 5 more

Open Access

https://doi.org/10.1038/s41598-017-11118-y

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Abstract

CLEC14a (C-type lectin domain family 14 member) is a tumor endothelial cell marker protein that is known to play an important role in tumor angiogenesis, but the basic molecular mechanisms underlying this function have not yet been clearly elucidated. In this study, using various proteomic tools, we isolated a 70-kDa protein that interacts with the C-type lectin-like domain of CLEC14a (CLEC14a-CTLD) and identified it as heat shock protein 70-1A (HSP70-1A). Co-immunoprecipitation showed that HSP70-1A and CLEC14a interact on endothelial cells. In vitro binding analyses identified that HSP70-1A specifically associates with the region between amino acids 43 and 69 of CLEC14a-CTLD. Competitive blocking experiments indicated that this interacting region of CLEC14a-CTLD significantly inhibits HSP70-1A-induced extracellular signal-regulated kinase (ERK) phosphorylation and endothelial tube formation by directly inhibiting CLEC14a-CTLD-mediated endothelial cell-cell contacts. Our data suggest that the specific interaction of HSP70-1A with CLEC14a may play a critical role in HSP70-1A-induced angiogenesis and that the HSP70-1A-interacting region of CLEC14a-CTLD may be a useful tool for inhibiting HSP70-1A-induced angiogenesis.

Highlights

Angiogenesis is a physiological process through which new blood vessels are grown from pre-existing vessels
Increasing evidence supports the functional importance of CLEC14a in tumor angiogenesis, the related regulatory mechanism has not been intensively studied
We propose for the first time that HSP70-1A may directly interact with a region of CLEC14a-CTLD on endothelial cells, and that this interaction may be critical for HSP701A-induced angiogenesis

Summary

Introduction

Angiogenesis is a physiological process through which new blood vessels are grown from pre-existing vessels. Angiogenesis is finely regulated by many upregulated angiogenic factors, including ligands and receptors[2] It is closely associated with various angiogenesis-related diseases, including tumor progression, tumor metastasis, wet age-related macular degeneration, neovascular glaucoma, and diabetic retinopathy[3,4,5,6]. CLEC14a (C-type lectin domain family 14 member) is a 52-kDa tumor endothelial marker protein that is dominantly expressed on tumor vessels, but not on normal vessels[7]. It is a type I transmembrane protein whose extracellular domain (ECD) contains a C-type lectin-like domain (CLEC14a-CTLD), a sushi-like domain, and an epidermal growth factor-like domain[8]. Our findings suggest that HSP70-1A may be a novel binding partner of CLEC14a-CTLD, and that this interaction could critically regulate HSP70-1A-induced angiogenesis

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