Abstract: TH-PO0618
FSGS-Associated Myosin1e Mutations Disrupt Its Motor Activity and Intracellular Localization
Session Information
- Monogenic Kidney Diseases: Glomerular
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1201 Genetic Diseases of the Kidneys: Monogenic Kidney Diseases
Authors
- Sayeeda, Kazi, SUNY Upstate Medical University, Syracuse, New York, United States
- Ge, Jinghua, Penn State College of Medicine, Hershey, Pennsylvania, United States
- O'Connor, Thomas, SUNY Upstate Medical University, Syracuse, New York, United States
- Yengo, Christopher, Penn State College of Medicine, Hershey, Pennsylvania, United States
- Krendel, Mira, SUNY Upstate Medical University, Syracuse, New York, United States
Background
Myosin1e (Myo1e) is an actin-dependent motor protein enriched in podocytes. Disruption of the actin cytoskeletal organization compromises podocyte structure and glomerular barrier integrity. Mutations in the MYO1E gene have been linked to focal segmental glomerulosclerosis (FSGS). In this project, we have analyzed recently identified MYO1E mutations associated with FSGS (Warejko et al., 2018; Krendel et al., 2023) that have not been functionally characterized.
Methods
To assess the effects of disease-associated mutations on Myo1e subcellular localization, EGFP-tagged Myo1e constructs were introduced into Myo1e-KO podocyte-derived cells via adenoviral transduction. In parallel, we used the insect cell expression system to purify mutant and WT Myo1e proteins for functional testing of the ATPase and motor activity. Myo1e proteins containing motor and neck domains and C-terminal purification tags were expressed in SF9 insect cells using baculoviral vectors.
Results
In the Myo1e-KO podocyte-like cells, EGFP-tagged WT Myo1e localized to cell-cell junctions and colocalized with actin, consistent with the pattern observed in the WT podocytes. In contrast, the mutants exhibited cytoplasmic localization. The G562R mutant occasionally formed puncta near cellular junctions but lacked WT-like enrichment. Fluorescence Recovery After Photobleaching (FRAP) analysis showed that these puncta were mostly non-dynamic, suggesting possible misfolded aggregate formation. Biochemical assays revealed loss of actin-activated ATPase activity in the G562R and E410K mutants and a reduction of ATPase activity in the A92E mutant. In vitro motility assays confirmed reduced velocity for A92E, while other mutants were non-motile.
Conclusion
FSGS-associated Myo1e mutations disrupt Myo1e junctional targeting and lead to reduced or absent motor activity.
Funding
- NIDDK Support