Abstract
Signal regulatory protein-alpha (SIRP alpha) is a member of the Ig superfamily selectively expressed by neuronal and myeloid cells. The molecule mediates functional interactions with CD47/integrin-associated protein. Here we provide evidence for the tissue-specific glycosylation of neuronal and haematopoietic SIRP alpha. We demonstrate a major difference in the galactosylation of N-linked glycans isolated from neuronal (i.e. brain-derived) SIRP alpha as compared to myeloid (i.e. spleen-derived) SIRP alpha, with neuronal SIRP alpha almost completely lacking galactose. beta 4-galactosyltransferase assays demonstrated that this is most likely due to a low galactosylation capacity of the brain. In order to investigate the role of galactosylation of SIRP alpha in cellular interactions, soluble recombinant SIRP alpha glycoforms containing galactose (SIRP alpha-Fc) or lacking galactose (SIRP alpha(Delta Gal)-Fc) were produced. Binding studies demonstrated superior binding of SIRP alpha(Delta Gal)-Fc to cerebellar neurons and isolated lymphocytes. In contrast, SIRP alpha-Fc bound relatively strong to macrophages. These data show that the galactosylation of SIRP alpha determines its cellular binding specificity.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.