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CHIP-dependent regulation of the actin cytoskeleton is linked to neuronal cell membrane integrity.

ABSTRACT: CHIP is an E3-ubiquitin ligase that contributes to healthy aging and has been characterized as neuroprotective. To elucidate dominant CHIP-dependent changes in protein steady-state levels in a patient-derived human neuronal model, CHIP function was ablated using gene-editing and an unbiased proteomic analysis conducted to compare knock-out and wild-type isogenic induced pluripotent stem cell (iPSC)-derived cortical neurons. Rather than a broad effect on protein homeostasis, loss of CHIP function impacted on a focused cohort of proteins from actin cytoskeleton signaling and membrane integrity networks. In support of the proteomics, CHIP knockout cells had enhanced sensitivity to induced membrane damage. We conclude that the major readout of CHIP function in cortical neurons derived from iPSC of a patient with elevate α-synuclein, Parkinson's disease and dementia, is the modulation of substrates involved in maintaining cellular "health". Thus, regulation of the actin cytoskeletal and membrane integrity likely contributes to the neuroprotective function(s) of CHIP.

SUBMITTER: Dias C

PROVIDER: S-EPMC8350547 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Pathway Analysis of Dominant CHIP E3 Ligase-Dependent Protein Steady State Changes Highlight a Role in Neuronal Cell Membrane Integrity Linked to the Actin Cytoskeleton

Project description:Functional integrity of the E3-ubiquitin ligase CHIP is essential for healthy aging in the brain. By virtue of its association with the core molecular chaperone machinery, studies into the physiological role(s) of CHIP have been dominated by its involvement in the quality control and degradation of unfolded, aggregated and/or mutated proteins. To elucidate the dominant CHIP-dependent changes in protein steady state levels in human neurons we conducted an unbiased proteomic analysis in genetically engineered wild-type and CHIP knockout iPSC-derived cortical neurons. Rather than a broad effect on protein homeostasis, pathway analysis highlighted a focused cohort of CHIP-responsive proteins involved in actin cytoskeleton signalling and membrane integrity. In support of the pathway analysis CHIP KO cell-lines had enhanced sensitivity to mechanical and chemical membrane damage. Consistent with recent studies on the identification of a non-canonical HSP-independent E3-activity for CHIP, the lack of general quality control defects in knock-out cells suggests that the major readout of CHIP function in cortical neurons is the regulation of native folded substrates involved in maintaining cellular ‘health’. Thus, CHIP-mediated regulation of the of cytoskeletal- and membrane-related proteins is likely to make a vital contribute to the neuroprotective activity of CHIP.

2021-07-29 | PXD021404 | Pride

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Project description: Not available

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Extracellular Vesicles Mediate Mesenchymal Stromal Cell-Dependent Regulation of B Cell PI3K-AKT Signaling Pathway and Actin Cytoskeleton.

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