Regulation of Insulin Signaling by the Phosphatidylinositol 3,4,5-triphosphate Phosphatase SKIP Through the Scaffolding Function of Pak1
Overview
Authors
Affiliations
Skeletal muscle and kidney-enriched inositol polyphosphate phosphatase (SKIP) has previously been implicated in the regulation of insulin signaling in skeletal muscle. Here, we present the first report of the mechanisms by which SKIP specifically suppresses insulin signaling and the subsequent glucose uptake. Upon insulin stimulation, SKIP is translocated to the membrane ruffles, where it binds to the active form of Pak1, which mediates multiple protein complex formation with phosphatidylinositol 3,4,5-triphosphate (PIP(3)) effectors such as Akt2, PDK1, and Rac1; this leads to inactivation of these proteins. SKIP also promotes the inhibition of Rac1-dependent kinase activity and the scaffolding function of Pak1, which results in the dissociation of Akt2 and PDK1 from Pak1. Thus, specific suppression of insulin signaling is achieved via the spatiotemporal regulation of SKIP through the scaffolding function of Pak1. These interactions are the foundation of the specific and prominent role of SKIP in the regulation of insulin signaling.
Modulating PAK1: Accessory Proteins as Promising Therapeutic Targets.
Mirzaiebadizi A, Shafabakhsh R, Ahmadian M Biomolecules. 2025; 15(2).
PMID: 40001545 PMC: 11852631. DOI: 10.3390/biom15020242.
Zheng S, Zhao N, Feng C, Ma J Clin Exp Nephrol. 2024; 28(6):513-521.
PMID: 38416339 DOI: 10.1007/s10157-024-02468-9.
Srivastav S, van der Graaf K, Singh P, Utama A, Meyer M, McNew J Autophagy. 2023; 20(1):131-150.
PMID: 37649246 PMC: 10761077. DOI: 10.1080/15548627.2023.2249794.
Insulin Signaling Pathway Model in Adipocyte Cells.
Sheibani M, Jalali-Farahani F, Zarghami R, Sadrai S Curr Pharm Des. 2022; 29(1):37-47.
PMID: 36518037 DOI: 10.2174/1381612829666221214122802.
Vav2 catalysis-dependent pathways contribute to skeletal muscle growth and metabolic homeostasis.
Rodriguez-Fdez S, Lorenzo-Martin L, Fernandez-Pisonero I, Porteiro B, Veyrat-Durebex C, Beiroa D Nat Commun. 2020; 11(1):5808.
PMID: 33199701 PMC: 7669868. DOI: 10.1038/s41467-020-19489-z.