Figure 3. Loss of STK4 causes autophagy defects in C. elegans.

(A) Representative electron micrographs of muscle cells from 1-day-old wild-type (WT) and cst-1(tm1900)/Stk4 animals. Arrows indicate autophagic vesicles; ‘M’ indicates myofibers. Scale bar = 1 µm. Inset is an enlargement of the boxed area showing double membrane-bound autophagosomes.

(B) Quantification of autophagic vesicles (double-membrane autophagosomes and single-membrane autolysosomes) per section in the muscle of 1-day-old WT and cst-1(tm1900) animals, as shown in (A). Horizontal line indicates the mean. Data are the average of 3 independent experiments. **P < 0.01, Student’s t-test.

(C) Quantification of GFP::LGG-1-positive puncta in seam cells of WT and cst-1(tm1900). Day 1 adults were injected with 50 µM BafA or DMSO, and 2 h later, GFP::LGG-1 puncta were quantified. Mean ± SEM of ∼200 cells. Data are representative of 3 independent experiments. DMSO on its own has negligible effect on LGG-1 punta under several conditions tested (data not shown). RNAi of autophagy gene bec-1 decreased the number of GFP::LGG-1-positive puncta in cst-1(−) animals, consistent with these structures representing autophagic events (data not shown).

(D) Quantification of p62::GFP foci in animals represented in Figure S3A. See Figure S3A for region of quantification in head region. Mean ± SEM of ∼20 animals. Data are representative of 3 biological repeats.

For C & D, ***P < 0.001, **P < 0.01 to WT control, one-way ANOVA.

See also Figure S3.