FIG 6.

Cleavage of cell surface-expressed HKU4 spike using purified lysosomal extracts. The experiments were performed in the same way as for Fig. 5A, except that HKU4 spike (either wild type [WT] or containing an N762 mutation that removed a glycosylation site from the lysosomal protease motif) replaced MERS-CoV spike. The experiments were repeated five times, and representative results are shown.