AIF1L regulates actomyosin contractility and filopodial extensions in human podocytes

Abstract

Podocytes are highly-specialized epithelial cells essentially required for the generation and the maintenance of the kidney filtration barrier. This elementary function is directly based on an elaborated cytoskeletal apparatus establishing a complex network of primary and secondary processes. Here, we identify the actin-bundling protein allograft-inflammatory-inhibitor 1 like (AIF1L) as a selectively expressed podocyte protein in vivo. We describe the distinct subcellular localization of AIF1L to actin stress fibers, focal adhesion complexes and the nuclear compartment of podocytes in vitro. Genetic deletion of AIF1L in immortalized human podocytes resulted in an increased formation of filopodial extensions and decreased actomyosin contractility. By the use of SILAC based quantitative proteomics analysis we describe the podocyte specific AIF1L interactome and identify several components of the actomyosin machinery such as MYL9 and UNC45A as potential AIF1L interaction partners. Together, these findings indicate an involvement of AIF1L in the stabilization of podocyte morphology by titrating actomyosin contractility and membrane dynamics.

In-Depth Analysis of the Plasma Proteome in ME/CFS Exposes Disrupted Ephrin-Eph and Immune System Signaling

“…However, FAK1 (focal adhesion kinase 1) was not concomitantly reduced and instead slightly higher in our patient cohort, short of any further comparison to breast cancer. The human protein atlas (HPA, ) puts most of AIF1L proteins in the kidney and urinary bladder, where it is involved in the stabilization of podocyte morphology and focal adhesions through the actomyosin machinery [ 26 ]. AIF1L is also present in many other organs, including male and female reproductive tissues, brain, lungs, the digestive tract, the skin, as well as adipose and soft tissues.…”

EPB41L5 controls podocyte extracellular matrix assembly by adhesome-dependent force transmission

“…Human immortalized podocyte cells (from male donor) were previously described in detail and maintained according to described procedures (Saleem et al, 2002;Yasuda-Yamahara et al, 2018b). For all cell culture experiments, human immortalized podocytes were cultured in RPMI 1640 medium supplemented with Glutamine, 10% FCS, ITS and non-essential amino acids.…”

α-Parvin Defines a Specific Integrin Adhesome to Maintain the Glomerular Filtration Barrier

“…Interestingly, mutations in either core ( ITGA3 ) or adhesome -associated ( CD151 , ACTN4 ) genes have been identified as disease-associated mutations, prominently affecting podocyte function, resulting in severe glomerular pathologies 11 – 13 . Using cell-type–specific proteomics and transcriptome analysis, we and others expanded the knowledge about prototypical adhesion receptor proteins within specialized glomerular cell types 14 – 18 . These studies contributed to a concept of balanced reciprocal crosstalk between the adhesome and GBM composition 17 , 19 .…”