title: A single cell level measurement of StAR expression and activity in adrenal cells.
abstract: The Steroidogenic acute regulatory protein (StAR) directs mitochondrial cholesterol uptake through a C-terminal cholesterol binding domain (CBD) and a 62 amino acid N-terminal regulatory domain (NTD) that contains an import sequence and conserved sites for inner membrane metalloproteases. Deletion of the NTD prevents mitochondrial import while maintaining steroidogenesis but with compromised cholesterol homeostasis. The rapid StAR-mediated cholesterol transfer in adrenal cells depends on concerted mRNA translation, p37 StAR phosphorylation and controlled NTD cleavage. The NTD controls this process with two cAMP-inducible modulators of, respectively, transcription and translation SIK1 and TIS11b/Znf36l1. High-resolution fluorescence in situ hybridization (HR-FISH) of StAR RNA resolves slow RNA splicing at the gene loci in cAMP-induced Y-1 cells and transfer of individual 3.5 kB mRNA molecules to mitochondria. StAR transcription depends on the CREB coactivator CRTC2 and PKA inhibition of the highly inducible suppressor kinase SIK1 and a basal counterpart SIK2. PKA-inducible TIS11b/Znf36l1 binds specifically to highly conserved elements in exon 7 thereby suppressing formation of mRNA and subsequent translation. Co-expression of SIK1, Znf36l1 with 3.5 kB StAR mRNA may limit responses to pulsatile signaling by ACTH while regulating the transition to more prolonged stress.
authors: Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI 53706, United States.
authors: Jinwoo
authors: J
authors: Lee
authors: Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan.
authors: Takeshi
authors: T
authors: Yamazaki
authors: Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, United States.
authors: Hui
authors: H
authors: Dong
authors: Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI 53706, United States; Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, United States. Electronic address: jefcoate@wisc.edu.
authors: Colin
authors: C
authors: Jefcoate
mesh_terms: D000311:Adrenal Glands / Q000166:cytology* / Q000378:metabolism*; D000818:Animals; D002784:Cholesterol / Q000378:metabolism; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D059010:Single-Cell Analysis / Q000379:methods*; D014158:Transcription, Genetic; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D010750:Phosphoproteins; D000098682:Steroidogenic Acute Regulatory Protein; D002784:Cholesterol
keywords: CRTC; SIK; StAR; Steroidogenesis; TIS11B