Mitochondria are essential organelles that harbor a reduced genome, and expression of that genome requires regulated metabolism of its transcriptome by nuclear-encoded proteins. Despite extensive investigation, a comprehensive map of the yeast mitochondrial transcriptome has not been developed and all of the RNA-metabolizing proteins have not been identified, both of which are prerequisites to elucidating the basic RNA biology of mitochondria. Here, we present a mitochondrial transcriptome map of the yeast S288C reference strain. Using RNAseq and bioinformatics, we show the expression level of all transcripts, revise all promoter, origin of replication, and tRNA annotations, and demonstrate for the first time the existence of alternative splicing, mirror RNAs, and a novel RNA processing site in yeast mitochondria. The transcriptome map has revealed new aspects of mitochondrial RNA biology and we expect it will serve as a valuable resource. As a complement to the map, we present our compilation of all known yeast nuclear-encoded ribonucleases (RNases), and a screen of this dataset for those that are imported into mitochondria. We sought to identify RNases that are refractory to recovery in traditional mitochondrial screens due to an essential function or eclipsed accumulation in another cellular compartment. Using this in silico approach, the essential RNase of the nuclear and cytoplasmic exosome, Dis3p, emerges as a strong candidate. Bioinformatics and in vivo analyses show that Dis3p has a conserved and functional mitochondrial-targeting signal (MTS). A clean and marker-less chromosomal deletion of the Dis3p MTS results in a defect in the decay of intron and mirror RNAs, thus revealing a role for Dis3p in mitochondrial RNA decay.

Background: LMAN1 is an important mammalian cargo receptor for endoplasmic reticulum (ER)-to-Golgi trafficking. Results: Crystal structures pinpoint critical residues on LMAN1 for mannose binding, which is sensitive to Ca

TPS2646 Background: CD73 expression is elevated in tumors and contributes to increasing levels of immunosuppressive adenosine in the tumor microenvironment. CD73 knockout mice exhibit reduced tumor growth and resistance to experimental metastasis. Inhibition of CD73 activity with an anti-CD73 antibody blocks adenosine production, shown to inhibit tumor growth in syngeneic models. CPI-006 is a humanized IgG1 FcγR binding-deficient anti-CD73 antibody now being investigated in this Phase 1/1b multicenter, open label trial as single agent (SA) or combination with CPI-444, an oral, small molecule, selective A2aR antagonist or in combination with pembrolizumab, an anti-PD1 indicated for the treatment of patients across a number of malignancies (NCT03454451). Methods: Up to 462 subjects will be enrolled at approximately 35 sites in the US, Canada and Australia. Eligible patients must have: non-small cell lung, renal cell carcinoma, urothelial bladder, cervical, colorectal, ovarian, pancreatic, prostate, head and neck, triple-negative breast, endometrial, select sarcomas and non-Hodgkin lymphoma malignancies relapsed, refractory or intolerant to 1 to 5 standard therapies; aged ≥ 18 yo; adequate organ function and measurable disease. The objectives of the study are 1) evaluate the safety and tolerability of SA CPI-006, in combination with CPI-444 and in combination with pembrolizumab, 2) evaluate the pharmacokinetics of each regimen and 3) identify potential biomarker signals predictive of response. Study design in table. Study Design. Clinical trial information: NCT03454451. [Table: see text]