Table 1. Lysosomal pH values of control, CLN2 and CLN3 fibroblasts incubated in high and low proteolysis media.

	High Proteolysis		Low Proteolysis
	RFU	pH	RFU	pH
CONTROL	78.1±11.7	5.5±0.2	54.1±8.5	4.8±0.2
CLN2	67.6±10.3	5.3±0.2	50.6±12.1	4.7±0.3
CLN3	117.0±15.2	6.1±0.2**	86.5±10.9	5.5±0.2**

The mean fluorescence intensity values for each cell and condition, obtained in three separate experiments with duplicated samples, were interpolated in the corresponding calibration curves (see Figure S4). Stars indicate statistically significant differences from control values (**p<0.01).