Figure 4

Functional analysis of CTNS mutants. (a) Functional analysis of loss of function patient mutation S141F. Transformant’s were serial diluted and spotted on minimal media containing 200 µM Methionine, & different concentration of cystine as described in experimental procedures. The photographs were taken after 2–3 days of incubation at 30 °C. The experiment was repeated with three independent transformations. (b) Gain of function mutants The S. cerevisiae met15Δyct1Δ strain (ABC 1580) was separately transformed with WT CTNS, CTNS-Δgydql, p416-TEF (control vector) and the different gain of function mutants expressed under the TEF promoter. (c) Gain-of-function mutations mapped on the CTNS topology.