STIP1 and glaucoma: As shown in Figure 3, growth of the sti1- null strain is inhibited in the presence of 39 μM radicicol, but normal growth is restored in the strains transformed with either the wild-type or the K470R constructs of yeast STI1, indicating that K470R (homologous to the glaucoma-associated K434R variant) did not functionally impair Sti1p's activity in this assay.