Proteasome subunit beta type 1 interacts directly with Rheb and regulates the cell cycle in Cashmere goat fetal fibroblasts

Yanfeng Wang,Zhixin Guo,Mingtao Liu,Keyu Zhao,Xue Feng,Xu Zheng,Xiaojing Wang,Huifang Hao,Xudong Guo,Zhigang Wang

doi:10.1080/19768354.2017.1371072

Yanfeng Wang, Zhixin Guo + Show 8 more

Open Access

https://doi.org/10.1080/19768354.2017.1371072

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Abstract

ABSTRACTPSMB1 (proteasome subunit beta type 1) is a core component of the 20S proteasome, and based on its structure, it might have a crucial function in the transcription of certain genes. Rheb (Ras homolog enriched in brain) is a Ras-like small GTPase that acts as an upstream positive regulator of the mechanistic target of rapamycin complex 1 (mTORC1) pathway. We cloned and characterized PSMB1 (KY310590.1) to determine its function in cell cycle progression and proliferation of goat fetal fibroblasts (GFbs). Further, by yeast two-hybrid screen and coimmunoprecipitation, we conformed that PSMB1 interacts directly with Rheb. An siRNA was designed and expressed targeting PSMB1 mRNA in GFbs and inducing cell cycle arrest. Rheb overexpression in GFbs significantly increased the number of S phase cells and growth efficiency compared with control cells. These data indicate that PSMB1 and Rheb have important functions in the cell cycle and proliferation of GFbs, indicating that their interaction governs many processes in GFbs.Abbreviations: GFbs: Cashmere goat fetal fibroblasts; mTOR: The mechanistic target of rapamycin; PSMB1: proteasome subunit beta type 1; Rheb: Ras homolog enriched in brain

Highlights

The 20S proteasome is a core particle of the ubiquitin–26S proteasome complex and has important functions in many cellular processes, regulating the levels of key molecules in cell cycle progression, antigen presentation, secretory pathways, and signal transduction (Yuan et al 2013)
Rheb (Ras homolog enriched in brain) belongs to the Ras family and was first identified in 1994 in a screen for genes that are induced in neurons in response to synaptic activity (Kang et al 2015)
Our results indicate that proteasome subunit beta type 1 (PSMB1) interacts with Rheb and regulates cell cycle progression in goat fetal fibroblasts (GFbs)

Summary

Introduction

The 20S proteasome is a core particle of the ubiquitin–26S proteasome complex and has important functions in many cellular processes, regulating the levels of key molecules in cell cycle progression, antigen presentation, secretory pathways, and signal transduction (Yuan et al 2013). PSMB1 (proteasome subunit beta type 1) is a core component of the 20S proteasome, and its structure has been studied extensively (Wang et al 2013). PSMB1 is believed to be crucial for the transcription of certain genes (Inoue et al 2010; Yamauchi et al 2013), correlate with type 1 diabetes (Bradfield et al 2011), maintain stem cell integrity of human bone marrow stromal cells (hBMSCs) (Lu et al 2012), and be linked to the occurrence and progression of cancer (Barton et al 2013; Jia et al 2015). Rheb predominates over Rheb in the regulation of mechanistic target of rapamycin complex 1 (mTORC1) in vivo (Zou et al 2011)

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