We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Existence of NEU1 sialidase on mouse thymocytes whose natural substrate is CD5.
- Authors
Shigeko Kijimoto-Ochiai; Tokuko Matsumoto-Mizuno; Daisuke Kamimura; Masaaki Murakami; Miwako Kobayashi; Ichiro Matsuoka; Hiroshi Ochiai; Hideharu Ishida; Makoto Kiso; Keiko Kamimura; Toshiaki Koda
- Abstract
Membrane-bound sialidases in themouse thymus are unique and mysterious because their activity at pH 6.5 is equal to or higher than that in the acidic region. The pH curve like this has never been reported in membrane-bound form. To clarify this enzyme, we studied the sialidase activities of crude membrane fractions from immature-T, mature-T and non-T cells from C57BL/6 mice and from SM/J mice, a strain with a defect in NEU1 activity. Non-T cells fromC57BL/6 mice had high activity at pH 6.5, but those from SM/J mice did not. Neu1 and Neu3 mRNA was shown by real-time PCR to be expressed in T cells and also in non-T cells, whereas Neu2 was expressed mainly in non-T cells and Neu4 was scarcely expressed. However, the in situ hybridization study on the localization of four sialidases in the thymus showed that Neu4 was clearly expressed. We then focused on a sialidase on the thymocyte surface because the possibility of the existence of a sialidase on thymocytes was suggested by peanut agglutinin (PNA) staining after incubation of the cells alone in PBS. This activity was inhibited by NEU1-selective sialidase inhibitor C9-butyl-amide-2-deoxy-2,3-dehydro-N-acetylneuraminic acid. The natural substrate for the cell surface sialidase was identified as clustered differentiation 5 (CD5) by PNA-blot analysis of anti-CD5 immunoprecipitate. We conclude that NEU1 exists on the cell surface of mouse thymocytes and CD5 is a natural substrate for it. Although this is not themain reaction of themembrane-bound thymus-sialidases, itmust be important for the thymus.0
- Subjects
NEURAMINIDASE; THYMOCYTES; T cells; IMMUNOPRECIPITATION; THYMUS
- Publication
Glycobiology, 2018, Vol 28, Issue 5, p306
- ISSN
0959-6658
- Publication type
Article
- DOI
10.1093/glycob/cwy009