Steroid-Resistant Nephrotic Syndrome-Associated MYO1E Mutations Have Differential Effects on Myosin 1e Localization, Dynamics, and Activity

Pei Ju Liu, Laura K. Gunther, Michael E. Garone, Chunling Zhang, Diana Perez, Jing Bi-Karchin, Christopher D. Pellenz, Sharon E. Chase, Maria F. Presti, Eric L. Plante, Claire E. Martin, Svjetlana Lovric, Christopher M. Yengo, Friedhelm Hildebrandt, Mira Krendel

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Background Myo1e is a nonmuscle motor protein enriched in podocytes. Mutations in MYO1E are associated with steroid-resistant nephrotic syndrome (SRNS). Most of the MYO1E variants identified by genomic sequencing have not been functionally characterized. Here, we set out to analyze two mutations in the Myo1e motor domain, T119I and D388H, which were selected on the basis of protein sequence conservation. Methods EGFP-tagged human Myo1e constructs were delivered into the Myo1e-KO mouse podocyte-derived cells via adenoviral infection to analyze Myo1e protein stability, Myo1e localization, and clathrin-dependent endocytosis, which is known to involve Myo1e activity. Furthermore, truncated Myo1e constructs were expressed using the baculovirus expression system and used to measure Myo1e ATPase and motor activity in vitro. Results Both mutants were expressed as full-length proteins in the Myo1e-KO cells. However, unlike wild-type (WT) Myo1e, the T119I variant was not enriched at the cell junctions or clathrin-coated vesicles (CCVs). In contrast, D388H variant localization was similar to that of WT. The rate of dissociation of the D388H variant from cell-cell junctions and CCVs was decreased, suggesting this mutation affects Myo1e interactions with binding partners. ATPase activity and ability to translocate actin filaments were drastically reduced for the D388H mutant, supporting findings from cell-based experiments. Conclusions T119I and D388H mutations are deleterious to Myo1e functions. The experimental approaches used in this study can be applied to future characterization of novel MYO1E variants associated with SRNS.

Original languageEnglish (US)
Pages (from-to)1989-2007
Number of pages19
JournalJournal of the American Society of Nephrology
Volume33
Issue number11
DOIs
StatePublished - Nov 2022

All Science Journal Classification (ASJC) codes

  • General Medicine

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