1. Peptides derived from the human transferrin receptor stimulate endosomal acidification via a Gi-type protein1 
Juan Codina, Richard Gurich, Thomas D. DuBose 
Kidney International 
Volume 55, Issue 6, Pages (June 1999)
DOI: /j x
Copyright © 1999 International Society of Nephrology Terms and Conditions

2. Figure 1
Representative tracing of the effects of PEP1 plus guanine 5′-triphosphate (GTP) on endosomal acidification. The ordinate represents florescence in arbitrary units (×103). The abscissa is time in seconds. The reaction was initiated by the addition of adenosine 5′-triphosphate (ATP) at T = 0.
Kidney International  , DOI: ( /j x)
Copyright © 1999 International Society of Nephrology Terms and Conditions

3. Figure 2
Effect of PEP1 on endosomal acidification in the presence of GTP. To control for different initial rates of proton transport between different membrane preparations, data are expressed as the percentage change from control. Each individual concentration of PEP1 was tested between five and eight times (different membrane preparations) in the presence of 15 μm GTP with a Km of approximately 25nm.
Kidney International  , DOI: ( /j x)
Copyright © 1999 International Society of Nephrology Terms and Conditions

4. Figure 3
Alignment of synthetic peptide and mastoparan (Mast) sequences. The boxes show the clusters of basic amino acids that are thought to be important for biological activity. The symbol + or - at the end of the line represents the presence or absence of stimulation of acidification.
Kidney International  , DOI: ( /j x)
Copyright © 1999 International Society of Nephrology Terms and Conditions

5. Figure 4
Representative tracing of the effect of PEP3 plus GTP on endosomal acidification. Axes are the same as in Figure 1.
Kidney International  , DOI: ( /j x)
Copyright © 1999 International Society of Nephrology Terms and Conditions

6. Figure 5
Representative tracing of the effects of mastaparan plus GTP on endosomal acidification. Axes are the same as in Figure 1.
Kidney International  , DOI: ( /j x)
Copyright © 1999 International Society of Nephrology Terms and Conditions

7. Figure 6
Effects of synthetic peptides on [35S]GTPγS binding. (A) The effects of control (•), PEP1 (□), PEP2 (▪), and PEP3 (100 μm; ⋄) on the rate of [35S]GTPγS binding. (B) Effects of Mg+2 on [35S]GTPγS binding. The concentration of PEP1 was 100nm. [35S]GTPγS binding was measured at 10minutes.
Kidney International  , DOI: ( /j x)
Copyright © 1999 International Society of Nephrology Terms and Conditions