Dataset Information

Identification of phosphorylation sites of purified ORP8 from in vitro AMPK kinase assay

ABSTRACT: We investigated the potential role of AMPK in the phosphorylation of ORP8.In vitro kinase assay using purified ORP8 and kinase-active AMPK complex confirmed that ORP8 is the direct substrate of AMPK. Phosphorylated ORP8 from in vitro kinase assay was analyzed by HPLC-MS/MS.

INSTRUMENT(S): LTQ Orbitrap

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: maomao pu

LAB HEAD: Wei Liu

PROVIDER: PXD036201 | Pride | 2023-10-24

REPOSITORIES: Pride

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Publications

ORP8 acts as a lipophagy receptor to mediate lipid droplet turnover.

Pu Maomao M Zheng Wenhui W Zhang Hongtao H Wan Wei W Peng Chao C Chen Xuebo X Liu Xinchang X Xu Zizhen Z Zhou Tianhua T Sun Qiming Q Neculai Dante D Liu Wei W

Protein & cell 20230901 9

Lipophagy, the selective engulfment of lipid droplets (LDs) by autophagosomes for lysosomal degradation, is critical to lipid and energy homeostasis. Here we show that the lipid transfer protein ORP8 is located on LDs and mediates the encapsulation of LDs by autophagosomal membranes. This function of ORP8 is independent of its lipid transporter activity and is achieved through direct interaction with phagophore-anchored LC3/GABARAPs. Upon lipophagy induction, ORP8 has increased localization on L ...[more]

PMID: 37707322

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Project description:Steroid hormones regulate essential physiological processes and inadequate levels are associated with various pathological conditions. In testosterone-producing Leydig cells, steroidogenesis is strongly stimulated by LH via its receptor leading to increased cAMP production and expression of the steroidogenic acute regulatory (STAR) protein, which is essential for the initiation of steroidogenesis. Leydig cell steroidogenesis then passively decreases following the rapid degradation of cAMP into AMP by phosphodiesterases. In this study, we show that AMP-activated protein kinase (AMPK) is activated following cAMP breakdown in MA-10 and MLTC-1 Leydig cells. Activated AMPK then actively inhibits cAMP-induced steroidogenesis by repressing the expression of key regulators of steroidogenesis including Star and Nr4a1. Similar results were obtained in Y-1 adrenal cells and in the constitutive steroidogenic cell line R2C. Our data identify AMPK as an active repressor of steroid hormone biosynthesis in steroidogenic cells that is essential to preserve cellular energy and prevent excess steroid production. Steroid hormones regulate essential physiological processes and inadequate levels are associated with various pathological conditions. In testosterone-producing Leydig cells, steroidogenesis is strongly stimulated by LH via its receptor leading to increased cAMP production and expression of the steroidogenic acute regulatory (STAR) protein, which is essential for the initiation of steroidogenesis. Leydig cell steroidogenesis then passively decreases following the rapid degradation of cAMP into AMP by phosphodiesterases. In this study, we show that AMP-activated protein kinase (AMPK) is activated following cAMP breakdown in MA-10 and MLTC-1 Leydig cells. Activated AMPK then actively inhibits cAMP-induced steroidogenesis by repressing the expression of key regulators of steroidogenesis including Star and Nr4a1. Similar results were obtained in Y-1 adrenal cells and in the constitutive steroidogenic cell line R2C. Our data identify AMPK as an active repressor of steroid hormone biosynthesis in steroidogenic cells that is essential to preserve cellular energy and prevent excess steroid production. MA-10 Leydig cells were treated with either DMSO (control), 10 uM forskolin or forskolin+Aicar (1 mM) for 1.5 h before total RNA extraction

Dataset Information

Identification of phosphorylation sites of purified ORP8 from in vitro AMPK kinase assay

Publications

ORP8 acts as a lipophagy receptor to mediate lipid droplet turnover.

Similar Datasets

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