**4. Conclusions**

In this review article, we have summarized the current evidence regarding the role of UPS in BP regulation, especially focusing on sodium reabsorption in the kidney and vascular functions (Figure 1). In the kidney, sodium reabsorption regulated by NEDD4-2 has been well characterized in principal cells and has been extensively analyzed in other nephron segments. Studies have also demonstrated the emerging roles of other mechanisms including CUL3 and KLHL3. In addition, accumulating evidence reveals the involvement of vascular functions in UPS-mediated BP regulation. Given that UPS is present ubiquitously and elicits multiple functions, future investigation is necessary for the complete elucidation of the precise role of UPS in modulating BP.

**Author Contributions:** Writing–Original Draft Preparation, O.Y. and D.H.; Writing–Review & Editing, K.I. and S.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported in part by JSPS KAKENHI grants 19H03678 (S.S.).

**Conflicts of Interest:** The authors declare no conflict of interest.
