The mitochondrial inner membrane consists of two domains, inner boundary membrane and cristae membrane that are connected by crista junctions. Mitofilin/Fcj1 was reported to be involved in formation of crista junctions, however, different views exist on its function and possible partner proteins. We report that mitofilin plays a dual role. Mitofilin is part of a large inner membrane complex, and we identify five partner proteins as constituents of the mitochondrial inner membrane organizing system (MINOS) that is required for keeping cristae membranes connected to the inner boundary membrane. Additionally, mitofilin is coupled to the outer membrane and promotes protein import via the mitochondrial intermembrane space assembly pathway. Our findings indicate that mitofilin is a central component of MINOS and functions as a multifunctional regulator of mitochondrial architecture and protein biogenesis.

The mechanisms that underlie the oxidative biogenesis of mitochondrial proteins catalyzed by disulfide carrier Mia40 and thiol oxidase Erv1 are not fully understood. This study identifies dynamics of the Mia40–substrate intermediate complex and shows that Erv1 directly participates in Mia40–substrate dynamics by forming a ternary complex.

This study provides evidence supporting the presence of erythrocytes deficient in CD55 presentation in HS and hereditary microcytosis. Moreover, deficiency of CD55 antigen presentation on RBC does not correlate with the amount of CD55 in RBC membrane. Further studies using molecular techniques will clarify the exact participation of CD55 deficiency in premature RBC clearance in HHA.

Translation of viral proteins from subgenomic RNAs (sgRNAs) is a common strategy among positive-stranded RNA viruses. Unlike host mRNA, sgRNA of Potato leafroll virus (PLRV) does not possess a cap at its 5' end nor a poly(A) tail at the 3' terminus, both of which are known to be crucial for translation of RNA in eukaryotic cells. Here, we demonstrate, that in wheat germ extract (WGE) truncation of the sgRNA1 5' UTR increases translation efficiency, as it has previously been observed in rabbit reticulocyte lysate (RRL), whereas removal of the 3' UTR does not affect translation. We also describe two regulatory elements located within the coding sequence of the coat protein (CP) gene and its read-through domain (RTD) and are responsible for regulation of in vitro translation of the PLRV sgRNA1. The frst element is composed of the purine sequence AAAGGAAA located between the AUG codons of the CP and 17K genes. Deletion of this domain or its substitution by pyrimidines reduced by half the translation of both genes, whereas deletion of the RTD resulted in a 3.6-fold reduction in translation efficiency. This is the first report of translation regulatory elements of plant viruses located within a coding region.

Background Rheumatoid arthritis (RA) is a chronic autoimmune disease with systemic inflammation finally resulting in damaged joints. One of the RA development models suggests bone marrow (BM) as a place of inflammation development further leading to disease progression. We aimed to investigate the potential of CTLA-4-Fc molecule in inducing tolerogenic milieu in BM measured as indoleamine 2,3-dioxygenase (IDO) expression, CD4 + Foxp3 + Treg induction, and T cell activation control. The expression of IDO-pathway genes was also examined in monocytes to estimate the tolerogenic potential in the periphery. Methods Bone marrow mononuclear cells (BMMC) were stimulated by pro-inflammatory cytokines and CTLA-4-Fc. Next IDO expression, CD4 + CD69 + and CD4 + Foxp3 + percentage were estimated by PCR and FACS staining, respectively. Enzymatic activity of IDO was confirmed by HPLC in BM plasma and blood plasma. Genes expressed in IDO-pathway were analyzed by NGS in peripheral monocytes isolated from RA patients and healthy controls. Results We found that CTLA-4-Fc and IFN-γ stimulation results in IDO production by BMMC. CTLA-4-Fc induced tryptophan catabolism can inhibit mitogen-induced CD4 + T cells activation without influencing CD8 + cells, but did not control CD25 nor Foxp3 expression in BM cells. Significantly higher expression of selected IDO-pathway genes was detected on peripheral monocytes isolated from RA as compared to healthy controls. Conclusion This study sheds light on some immunosuppression aspects present or induced in BM. The potential of IDO-mediated pathways were confirmed in the periphery, what may represent the promising candidates for therapeutic strategies in RA.