Figure 4. The Q268X mutation abolishes membrane association of syntaxin 11 in YTS NK cells.
(A) Analysis of the membrane association of syntaxin 11 expressed endogenously in YTS NK cells. Postnuclear supernatants from YTS NK cells were fractionated by centrifugation into pellet (membrane) and supernatant (cytosolic) fractions. The fractions were resolved by SDS-PAGE and immunoblots probed with antibodies specific for syntaxin 11, SNAP23, calnexin and GAPDH. (B) Analysis of the membrane association of GFP-syntaxin 11 and GFP-syntaxin 11 Q268X in YTS NK cells. Postnuclear supernatants of YTS cells transfected with either GFP-syntaxin 11 or GFP syntaxin 11 Q268X were fractionated by centrifugation into membrane and cytosolic fractions. The fractions were resolved by SDS-PAGE and GFP-syntaxin 11 fusion proteins detected by probing immunoblots with a rabbit syntaxin 11 specific antibody.