The stress response and cell survival are necessary for normal pancreatic β-cell function, glucose homeostasis, and prevention of diabetes. The homeodomain transcription factor and human diabetes gene pancreas/duodenum homeobox protein 1 (Pdx1) regulates β-cell survival and endoplasmic reticulum stress susceptibility, in part through direct regulation of activating transcription factor 4 (Atf4). Here we show that Atf5, a close but less-studied relative of Atf4, is also a target of Pdx1 and is critical for β-cell survival under stress conditions.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2012
Activating transcription factor 5 (ATF5) is a member of the ATF/cAMP response element-binding family of transcription factors, which compose a large group of basic region leucine zipper proteins whose members mediate diverse transcriptional regulatory functions. ATF5 has a well-established prosurvival activity and has been found to be overexpressed in several human cancers, in particular glioblastoma. However, the role(s) of ATF5 in development and normal physiology are unknown.
View Article and Find Full Text PDFHematologic malignancies are typically associated with leukemogenic fusion proteins, which are required to maintain the oncogenic state. Previous studies have shown that certain oncogenes that promote solid tumors, such as RAS and BRAF, can induce senescence in primary cells, which is thought to provide a barrier to tumorigenesis. In these cases, the activated oncogene elicits a DNA damage response (DDR), which is essential for the senescence program.
View Article and Find Full Text PDFLipocalin 24p3 is a secreted protein that can induce apoptosis in cells containing the 24p3 cell surface receptor, 24p3R. The oncoprotein BCR-ABL activates 24p3 and represses 24p3R expression. Thus, BCR-ABL(+) cells synthesise and secrete 24p3, which induces apoptosis in normal 24p3R-containing cells but not in BCR-ABL(+) cells.
View Article and Find Full Text PDFMolecular mechanisms that control oligodendrocyte myelination during mammalian central nervous system (CNS) development are poorly understood. In this study, we identified Zfp488, an oligodendrocyte-specific zinc-finger transcription regulator, by screening for genes downregulated in the optic nerves of Olig1-null mice. The predicted primary structure of Zfp488 is evolutionarily conserved in vertebrates and invertebrates.
View Article and Find Full Text PDFBackground: In yeast, birds and mammals, the SAPK-interacting protein 1 (Sin1) gene product has been implicated as a component of the stress-activated protein kinase (SAPK) signal transduction pathway. Recently, Sin1 has also been shown to interact with the carboxyl terminal end of the cytoplasmic domain of the ovine type I interferon receptor subunit 2 (IFNAR2). However, the function of Sin1 remains unknown.
View Article and Find Full Text PDFDuring early pregnancy in ruminants, a type I interferon (IFN-tau) signals from the conceptus to the mother to ensure the functional survival of the corpus luteum. IFN-tau operates through binding to the type I IFN receptor (IFNR). Here we have explored the possibility that IFNAR2, one of the two subunits of the receptor, might interact with hitherto unknown signal transduction factors in the uterus that link IFN action to pathways other than the well established Janus kinase-signal transducer and activator of transcription pathways.
View Article and Find Full Text PDF