Fig. 3. Efficiency of sorting of proinsulin to the regulated secretory pathway is unaffected by Hub. Cells were infected with recombinant adenovirus expressing only EGFP (control) or EGFP and Hub (Hub). Those cells expressing the highest levels of EGFP (and thus Hub) were sorted by FACS and pulse-labelled for 10 minutes with [³H]leucine before a 150 minute chase under basal conditions. Labelled proinsulin and insulin secreted during this time and that remaining within in the cells at the end of the incubation was quantified by HPLC (see Fig. 2). The percentage of labelled proinsulin directed to the regulated secretory pathway was calculated as 100—x, where x is the percentage of labelled proinsulin released without conversion during the 150 minute chase (and attributed to constitutive secretion) and is presented as mean±s.e.m., n=4. Note the interrupted scale. Sorting efficiency was >99% regardless of whether Hub was expressed in the cells or not.

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