A useful radiolabeling method for detection of T cell receptor glycoproteins bearing immature and mature N-linked glycans

Abstract

The antigen receptor expressed on most T lymphocytes, the T cell receptor (TCR), is a multisubunit complex containing TCRα,β and CD3-γ,δ,ε and ζ chains, in the form αβδεγεζζ. The intracellular transport of TCR proteins is routinely measured by the extent of processing of N-linked glycan chains present on TCRα,β and CD3γ,δ subunits, which are converted from immature (high mannose) oligosaccharides in the endoplasmic reticulum (ER) to mature (complex type) species within the Golgi complex. In the current study, a radiolabeling method is described that is useful for the study of TCR glycoproteins bearing immature and mature N-linked oligosaccharide chains. Specifically, we report the use of [ 3 H ] galactose as a radioactive tracer of TCR proteins containing glucose and galactose residues, present in immature and mature N-linked oligosaccharides, respectively. This technique is rapid, simple, and sensitive, and provides a unique approach for studying the processing and subcellular localization of T cell receptor proteins.