The N-terminal ectodomain of Ninjurin1 liberated by MMP9 has chemotactic activity

• Published in: Biochemical and biophysical research communications Vol. 428; no. 4; pp. 438 - 444
• Main Authors: Ahn, Bum Ju, Le, Hoang, Shin, Min Wook, Bae, Sung-Jin, Lee, Eun Ji, Wee, Hee-Jun, Cha, Jong Ho, Park, Ji-Hyeon, Lee, Hye Shin, Lee, Hyo-Jong, Jung, Hyunsook, Park, Zee-Yong, Park, Sang Ho, Han, Byung Woo, Seo, Ji Hae, Lo, Eng H., Kim, Kyu-Won
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 30.11.2012
• Subjects: Amino Acid Sequence; Animals; Cell Adhesion Molecules, Neuronal - chemistry; Cell Adhesion Molecules, Neuronal - genetics; Cell Adhesion Molecules, Neuronal - metabolism; Chemokines - chemistry; Chemokines - genetics; Chemokines - metabolism; Chemotactic Factors - chemistry; Chemotactic Factors - genetics; Chemotactic Factors - metabolism; Chemotaxis; HEK293 Cells; Humans; Kidney - metabolism; Leucine - chemistry; Liver - metabolism; Matrix Metalloproteinase 9 - chemistry; Mice; Mice, Inbred C57BL; MMP9; Molecular Sequence Data; Nerve Growth Factors - chemistry; Nerve Growth Factors - genetics; Nerve Growth Factors - metabolism; Ninjurin1; Posttranslational modification; Protein Structure, Secondary; Protein Structure, Tertiary; Proteolytic cleavage; Posttranslational modification; Ninjurin1; MMP9; Chemotaxis; Proteolytic cleavage
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2012.10.099

► We found the cleavage of Ninjurin1 in vector system and tissue lysates. ► MMP9 cleaved Ninjurin1 in between Leu56 and Leu57 on its N-terminal ectodomain. ► The liberated Ninjurin1 fragment has chemotactic activity. Ninjurin1 is known as an adhesion molecule promoting leukocyte trafficking under inflammatory conditions. However, the posttranslational modifications of Ninjurin1 are poorly understood. Herein, we defined the proteolytic cleavage of Ninjurin1 and its functions. HEK293T cells overexpressing the C- or N-terminus tagging mouse Ninjurin1 plasmid produced additional cleaved forms of Ninjurin1 in the lysates or conditioned media (CM). Two custom-made anti-Ninjurin1 antibodies, Ab1–15 or Ab139–152, specific to the N- or C-terminal regions of Ninjurin1 revealed the presence of its shedding fragments in the mouse liver and kidney lysates. Furthermore, Matrix Metalloproteinase (MMP) 9 was responsible for Ninjurin1 cleavage between Leu56 and Leu57. Interestingly, the soluble N-terminal Ninjurin1 fragment has structural similarity with well-known chemokines. Indeed, the CM from HEK293T cells overexpressing the GFP-mNinj1 plasmid was able to attract Raw264.7 cells in trans-well assay. Collectively, we suggest that the N-terminal ectodomain of mouse Ninjurin1, which may act as a chemoattractant, is cleaved by MMP9.