| First Author | Bae SJ | Year | 2017 |
| Journal | J Cell Biochem | Volume | 118 |
| Issue | 8 | Pages | 2219-2230 |
| PubMed ID | 28067406 | Mgi Jnum | J:294858 |
| Mgi Id | MGI:6458873 | Doi | 10.1002/jcb.25872 |
| Citation | Bae SJ, et al. (2017) Ninjurin1 Assembles Into a Homomeric Protein Complex Maintained by N-linked Glycosylation. J Cell Biochem 118(8):2219-2230 |
| abstractText | Ninjurin1 (Ninj1) is a cell surface protein known as a homophilic adhesion molecule. Previous studies have shown a trans-interaction of Ninj1 between immune cells and endothelial cells; however, little is known about Ninj1 modification and structure in the cis-interaction. We showed that Ninj1 assembles into a homomeric complex via a cis-interaction mediated by the intracellular region and N-glycosylation at Asn(60) . We identified cis-interaction between Ninj1 proteins using CFP- and YFP-tagged Ninj1 by Forster resonance energy transfer using a confocal microscope and fluorescence-activated cell sorter. We further observed the Ninj1 homomeric complexes composed of two to six monomeric Ninj1 molecules by a formaldehyde cross-linking assay. Co-immunoprecipitation assays with epitope-tagged truncated Ninj1 suggested that the intracellular region encompassing Leu(101) -Ala(110) participates in Ninj1 homomer assembly. Ninj1 N-glycosylation was characterized by treatment of tunicamycin and substitution of Asn to Gln or Ala. Fluorescence-activated cell sorting-based Forster resonance energy transfer assays further demonstrated that N-glycosylation is indispensable for the Ninj1 cis-interaction, and a formaldehyde cross-linking assay confirmed that interruption of N-glycosylation by Asn substitution disrupted Ninj1 homomeric complex formation. In silico analysis revealed that Ninj1 is highly conserved in vertebrates and that the conserved sequence contains an N-glycosylation motif and cis-interacting intracellular region, which participate in Ninj1 homomer assembly. Taken together, these data show that Ninj1 assembles into a homomeric protein complex and that N-glycosylation is a prerequisite for Ninj1 homomer assembly. J. Cell. Biochem. 118: 2219-2230, 2017. (c) 2017 Wiley Periodicals, Inc. |
