14-3-3 Proteins Stabilize Actin and Vimentin Filaments to Maintain Processes in Glomerular Podocyte

Adaptor protein 14-3-3s have isoform-specific binding partners and roles. We reported 14-3-3β interacts with FKBP12 and synaptopodin to maintain the structure of actin fibers in podocytes. However, differential roles of 14-3-3 isoforms in kidneys are unclear. Herein, we showed that 14-3-3β was dominantly co-localized with FKBP12 in foot processes and was partially co-localized with Par3 at slit diaphragm in podocytes. 14-3-3β interacted with Par3, and FKBP12 bound to 14-3-3β competitively with Par3. Although deletion of 14-3-3β enhanced the interaction of Par3-Par6, it altered actin fiber structure and processes. 14-3-3β and synaptopodin were downregulated in podocyte injury models. 14-3-3σ in podocytes interacted with vimentin in primary processes but not with the actin-associated proteins in foot processes. Deletion of 14-3-3σ altered vimentin fiber structure and processes. 14-3-3σ and vimentin were upregulated in the early phase of podocyte injury models but were decreased in the end stage. Together, the precise localization of 14-3-3β at actin cytoskeleton plays a role in maintaining foot processes and Par complex in podocytes. 14-3-3σ at vimentin cytoskeleton is essential for maintaining primary processes.