Short forms of Ste20-related proline/alanine-rich kinase (SPAK) in the kidney are created by aspartyl aminopeptidase (Dnpep)-mediated proteolytic cleavage

Abstract

Background: C-terminal SPAK fragments are found in kidney medulla. Results:Weidentified Dnpep as the protease responsible for SPAK cleavage, identified the sites of cleavage, and showed unusual preference for α helices. Conclusion: C-terminal SPAK fragments originate from Dnpep-mediated proteolytic cleavage. Significance: SPAK and its cleavage are significant for the regulation of renal Na+ reabsorption and control of blood pressure.