Biology subjects

Goldstrohm, A. C.

Publications and source records attributed to Goldstrohm, A. C..

2 recordsLinked to original sources

bioRxiv2020

Differential processing and localization of human Nocturnin controls metabolism of mRNA and nicotinamide dinucleotide metabolites

Nocturnin (NOCT) is a eukaryotic enzyme that belongs to a superfamily of exoribonucleases, endonucleases, and phosphatases. In this study, we analyze the expression, processing, localization, and cellular functions of human NOCT. We demonstrate that the NOCT protein is differentially expressed and processed in a cell and tissue type specific manner as a means to control its localization to the cytoplasm or mitochondria. Our studies also show that the N-terminus of NOCT is necessary and sufficient to confer mitochondrial localization. We then measured the impact of cytoplasmic NOCT on the transcriptome and report that it regulates the levels of hundreds of mRNAs that are enriched for components of signaling pathways, neurological functions, and regulators of osteoblast differentiation. Recent biochemical data indicate that NOCT dephosphorylates nicotinamide adenine dinucleotide (NAD) metabolites, and thus we measured the effect of NOCT on these cofactors in cells. We find that NOCT increases NAD(H) and decreases NADP(H) levels in a manner dependent on its intracellular localization. Collectively, our data indicate that NOCT can regulate levels of both mRNAs and NADP(H) cofactors in manner specified by its intracellular localization.

molecular biology↗

bioRxiv2019

Unique repression domains of Pumilio utilize deadenylation and decapping factors to accelerate destruction of target mRNAs.

Pumilio is an RNA-binding protein that represses a network of mRNAs to control embryogenesis, stem cell fate, fertility, and neurological functions in Drosophila. We sought to identify the mechanism of Pumilio-mediated repression and find that it accelerates degradation of target mRNAs, mediated by three N-terminal Repression Domains (RDs), which are unique to Pumilio orthologs. We show that the repressive activities of the Pumilio RDs depend on specific subunits of the Ccr4-Not (CNOT) deadenylase complex. Depletion of Pop2, Not1, Not2, or Not3 subunits alleviates Pumilio RD-mediated repression of protein expression and mRNA decay, whereas depletion of other CNOT components had little or no effect. Moreover, the catalytic activity of Pop2 deadenylase is important for Pumilio RD activity. Further, we show that the Pumilio RDs directly bind to the CNOT complex. We also report that the decapping enzyme, Dcp2, participates in repression by the N-terminus of Pumilio. These results support a model wherein Pumilio utilizes CNOT deadenylase and decapping complexes to accelerate destruction of target mRNAs. Because the N-terminal RDs are conserved in mammalian Pumilio orthologs, the results of this work broadly enhance our understanding of Pumilio function and roles in diseases including cancer, neurodegeneration, and epilepsy.

molecular biology↗