The cartilage-specific lectin C-type lectin domain family 3 member A (CLEC3A) enhances tissue plasminogen activator–mediated plasminogen activation

Abstract

C-type lectin domain family 3 member A (CLEC3A) is a poorly characterized protein belonging to the superfamily of C-type lectins. Its closest homologue tetranectin binds to the kringle 4 domain of plasminogen and enhances its association with tissue plasminogen activator (tPA) thereby enhancing plasmin production, but whether CLEC3A contributes to plasminogen activation is unknown. Here, we recombinantly expressed murine and human full-length CLEC3As as well as truncated forms of CLEC3A in HEK-293 Epstein-Barr nuclear antigen (EBNA) cells. We analyzed the structure of recombinant CLEC3A by SDS-PAGE and immunoblot, glycan analysis, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, size-exclusion chromatography, circular dichroism spectroscopy, and electron microscopy; compared the properties of the recombinant protein with those of CLEC3A extracted from cartilage; and investigated its tissue distribution and extracellular assembly by immunohistochemistry and immunofluorescence microscopy. We found that CLEC3A mainly occurs as a monomer, but also forms dimers and trimers, potentially via a coiled-coil α-helix. We also noted that CLEC3A can be modified with chondroitin/dermatan sulfate side chains and tends to oligomerize to form higher aggregates. We show that CLEC3A is present in resting, proliferating, and hypertrophic growth-plate cartilage and assembles into an extended extracellular network in cultures of rat chondrosarcoma cells. Further, we found that CLEC3A specifically binds to plasminogen and enhances tPA-mediated plasminogen activation. In summary, we have determined the structure, tissue distribution, and molecular function of the cartilage-specific lectin CLEC3A and show that CLEC3A binds to plasminogen and participates in tPA-mediated plasminogen activation.

Progression of acute-to-chronic atopic dermatitis is associated with quantitative rather than qualitative changes in cytokine responses

“…We identified a set of genes that are statistically differentially expressed only between chronic and acute lesions, while showing little changes between acute and nonlesional AD (Fig 2, B-D). These include genes that participate in skin barrier maintenance and repair (HRNR), IL-20, [14][15][16] immunoglobulin production (IGHG1, IGLC2, IGKC), inhibition of CD4 1 T-cell activation (CLEC3A), 17 and tryptophan metabolism (KYNU). 18 It is noteworthy that the immunoglobulins as a group have been identified as differentially expressed in chronic lesional skin of psoriasis and AD 8 ; in addition, KYNU, the L-kynureninase, which regulates tryptophan metabolism, can serve as an immune response modulator for chronic inflammatory conditions.…”

Novel Biomarkers Aim at Detecting Metastatic Sentinel Lymph Nodes in Breast Cancer

“…CLEC3A is a protein related to the great family of C-type lectins and can be seen in normal human breast tissue, but not in any other normal human tissue [15][16][17] . This protein is a heparin-binding, cell adhesion modulator that have capability to alter tumor cell invasion and metastasis by modulating tumor cell adhesion and the plasminogen/plasminogen-activator system [18] . Kallikreins are a subgroup of serine proteases, enzymes capable of cleaving peptide bonds in proteins, and a family of 15 genes on chromosome 19 [19] .…”

Overexpression of CLEC3A promotes tumor progression and poor prognosis in breast invasive ductal cancer

“… 14 Additionally, CLEC3A was reported to activate the plasminogen activation via enhancing tissue plasminogen activator. 15 It was found that plasminogen activator system was identified as one of the major mechanisms involved in the processes of cell invasion and metastatic spreading. 16 , 17 However, there is no direct evidence whether CLEC3A associates with clinicopathological significance in BC oncology and cancer progression.…”