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Lee, Young Hun,Park, Jun Hyoung,Cheon, Dong Huey,Kim, Taeyoung,Park, Yae Eun,Oh, Eok-Soo,Lee, Ji Eun,Lee, Seung-Taek Portland Press Ltd. 2017 Biochemical journal Vol. No.
<P>Syndecans (SDCs) are transmembrane proteoglycans that are involved in cell adhesion and cell communication. Specifically, SDC2 plays a key role in tumorigenesis, metastasis, and angiogenesis. Previously, we found that rat SDC2 is shed by matrix metalloproteinase-7 (MMP-7) in colon cancer cells. Here, we analyzed the susceptibility of rat SDC2 to various MMPs. We found that the rat SDC2 ectodomain (ECD) fused to the C-terminal Fc region, which was expressed in mammalian cells, was cleaved more efficiently by MMP-14 than MMP-7. Likewise, when anchored on the surface of HeLa cells, rat SDC2 was cleaved more efficiently by the treatment of MMP-14 than MMP-7 and was shed more readily by membrane-anchored MMP-14 than soluble MMP-14. Furthermore, MMP-14 cleaved recombinant SDC2-ECD expressed in <I>Escherichia coli</I> into multiple fragments. Using N-terminal amino acid sequencing and the top-down proteomics approach, we determined that the major cleavage sites were S<SUP>88</SUP>↓L<SUP>89</SUP>, T<SUP>98</SUP>↓M<SUP>99</SUP>, T<SUP>100</SUP>↓L<SUP>101</SUP>, D<SUP>132</SUP>↓P<SUP>133</SUP>, and N<SUP>148</SUP>↓L<SUP>149</SUP> for rat SDC2-ECD and S<SUP>55</SUP>↓G<SUP>56</SUP>, S<SUP>65</SUP>↓P<SUP>66</SUP>, P<SUP>75</SUP>↓K<SUP>76</SUP>, N<SUP>92</SUP>↓I<SUP>93</SUP> D<SUP>122</SUP>↓P<SUP>123</SUP>, and S<SUP>138</SUP>↓L<SUP>139</SUP> for human SDC2-ECD. Finally, the rat and human SDC2-ECD lost the ability to suppress vascular endothelial growth factor-induced formation of capillary-like tubes by human umbilical vein endothelial cells following cleavage by MMP-14, but its major cleavage-site mutant of rat SDC2-ECD did not. These results suggest that MMP-14 is a novel enzyme responsible for degrading SDC2 and impairing its physiological roles including angiogenesis.</P>
Kim, Yea ,Woon,Lee, Sungkung,Yun, Jangmi,Kim, AeRi Portland Press Ltd. 2015 Bioscience reports Vol.35 No.2
<▼1><P>Enhancers are closely positioned with actively transcribed target genes by chromatin looping. Non-coding RNAs are often transcribed on active enhancers, referred to as eRNAs (enhancer RNAs). To explore the kinetics of enhancer–promoter looping and eRNA transcription during transcriptional activation, we induced the β-globin locus by chemical treatment and analysed cross-linking frequency between the β-globin gene and locus control region (LCR) and the amount of eRNAs transcribed on the LCR in a time course manner. The cross-linking frequency was increased after chemical induction but before the transcriptional activation of gene in the β-globin locus. Transcription of eRNAs was increased in concomitant with the increase in cross-linking frequency. These results show that chromatin looping and eRNA transcription precedes the transcriptional activation of gene. Concomitant occurrence of the two events suggests functional relationship between them.</P></▼1><▼2><P>Chromatin looping between enhancer and promoter was generated after chemical induction but before the transcriptional activation of gene in the β-globin locus. Transcription of enhancer RNAs was increased in concomitant with the increase of chromatin looping in this locus.</P></▼2>