STIM2β is upregulated by insulin signaling and involved in adipogenesis

Abstract

Calcium ion play an important role in lipid formation and adipogenesis. The STIM1 and STIM2 are endoplasmic reticulum Ca2+ sensors which activate and regulate Orai, store operated calcium channel. I am interested in stim2β which is a splicing variant of STIM2 containing cassette exon 9 converting STIM2 from an activator to an inhibitor. To know the role of stim2β in adipogenesis, CRISPR system is applied. Through this process, I made several Stim2β knock out cell lines in NIH 3T3-L1 called as L1-S2β-KO #5, #13, and #14. As a result, Stim2β is not involved in proliferation through MTT assay but involved in early differentiation through Oil red O staining. In addition, Stim2β knock out cell lines show faster adipogenesis than wild type by observing expression difference of PPARγ2, aP2 which is differentiation positive markers. Also, Stim2β is affected by insulin signaling during adipogenesis. Generally, SOCE components are affected by insulin signaling, too. Especially, semi quantitative PCR and quantitative RT-PCR reveal that Stim2 isoforms have oscillation pattern after 24 hours of insulin treatment. Therefore, I suggest that regulation of STIM2β through insulin signaling can be potential therapeutic approach of obesity and related metabolic disorder.