Insertion of a myc-tag within alpha-dystroglycan domains improves its biochemical and microscopic detection

Results: We have generated two forms of DG polypeptides via the insertion of the myc-tag 1) within a flexible loop (between a. a. 170 and 171) that separates two autonomous subdomains, and 2) within the C-terminal domain in position 500. Their analysis showed that double-tagging (the beta-subunit is linked to GFP) does not significantly interfere with the correct processing of the DG precursor (pre-DG) and confirmed that the alpha-DG N-terminal domain is processed in the cell before alpha-DG reaches its plasma membrane localization. In addition, myc insertion in position 500, right before the second Ig-like domain of alpha-DG, proved to be an efficient tool for the detection and pulling-down of glycosylated alpha-DG molecules targeted at the membrane.