FIGURE 7.

Cartoon demonstrating the proposed bidirectional physiological transfer of Umod to the urinary space and to the tubulointerstitial space. As shown in Figure 6b, Umod is physiologically released from basolateral plasma membranes and membrane infoldings into the interstitium and enters the blood compartment (a). Umod serum levels are correlated with eGFR. sUmod concentrations may depend on the cellular integrity of the TAL segment. Therefore, sUmod might be released into serum at a decreased rate in renal injury (b).