| First Author | Alborzian Deh Sheikh A | Year | 2018 |
| Journal | Biochem Biophys Res Commun | Volume | 495 |
| Issue | 1 | Pages | 854-859 |
| PubMed ID | 29146181 | Mgi Jnum | J:273333 |
| Mgi Id | MGI:6280886 | Doi | 10.1016/j.bbrc.2017.11.086 |
| Citation | Alborzian Deh Sheikh A, et al. (2018) Proximity labeling of cis-ligands of CD22/Siglec-2 reveals stepwise alpha2,6 sialic acid-dependent and -independent interactions. Biochem Biophys Res Commun 495(1):854-859 |
| abstractText | Lectins expressed on the cell surface are often bound and regulated by the membrane molecules containing the glycan ligands on the same cell (cis-ligands). However, molecular nature and function of cis-ligands are generally poorly understood partly because of weak interaction between lectins and glycan ligands. Cis-ligands are most extensively studied in CD22 (also known as Siglec-2), an inhibitory B lymphocyte receptor specifically recognizing alpha2,6 sialic acids. CD22, CD45 and IgM are suggested to be ligands of CD22. Here we labeled molecules in the proximity of CD22 in situ on B cell surface using biotin-tyramide. Molecules including CD22, CD45 and IgM were labeled in wild-type but not ST6GalI(-/-) B cells that lack alpha2,6 sialic acids, indicating that these molecules associate with CD22 by lectin-glycan interaction, and are therefore cis-ligands. In ST6GalI(-/-) B cells, these cis-ligands are located in a slightly more distance from CD22. Thus, the lectin-glycan interaction recruits cis-ligands already located in the relative proximity of CD22 through non-lectin-glycan interaction to the close proximity. Moreover, cis-ligands are labeled in Cmah(-/-) B cells that lack Neu5Gc preferred by mouse CD22 as efficiently as in wild-type B cells, indicating that very low affinity lectin-glycan interaction is sufficient for recruiting cis-ligands, and can be detected by proximity labeling. Thus, proximity labeling with tyramide appears to be a useful method to identify cis-ligands and to analyze their interaction with the lectins. |
