Rsp5 Ubiquitin Ligase Is Required for Protein Trafficking in Saccharomyces cerevisiae COPI Mutants

Retrograde trafficking from the Golgi to the endoplasmic reticulum (ER) depends on the formation of vesicles coated with the multiprotein complex COPI. In Saccharomyces cerevisiae ubiquitinated derivatives of several COPI subunits have been identified. The importance of this modification of COPI proteins is unknown. With the exception of the Sec27 protein (β’COP) neither the ubiquitin ligase responsible for ubiquitination of COPI subunits nor the importance of this modification are known. Here we find that the ubiquitin ligase mutation, rsp5-1, has a negative effect that is additive with ret1-1 and sec28Δ mutations, in genes encoding α- and ε-COP, respectively. The double ret1-1 rsp5-1 mutant is also more severely defective in the Golgi-to-ER trafficking compared to the single ret1-1, secreting more of the ER chaperone Kar2p, localizing Rer1p mostly to the vacuole, and increasing sensitivity to neomycin. Overexpression of ubiquitin in ret1-1 rsp5-1 mutant suppresses vacuolar accumulation of Rer1p. We found that the effect of rsp5 mutation on the Golgi-to-ER trafficking is similar to that of sla1Δ mutation in a gene encoding actin cytoskeleton proteins, an Rsp5p substrate. Additionally, Rsp5 and Sla1 proteins were found by co-immunoprecipitation in a complex containing COPI subunits. Together, our results show that Rsp5 ligase plays a role in regulating retrograde Golgi-to-ER trafficking

A preliminary study on MTDH expression as a potential prognostic cancer marker

Background: Clinical studies have revealed that MTDH is overexpressed in various malignancies andis associated with disease progression and poor clinical outcomes. In order to study MTDH prognosticpotential, we decided to evaluate MTDH expression changes using cancerous and non-cancerous cellslines. Secondly, for the first time, we evaluated MTDH expression in prostate cancer cell lines representingdifferent metastatic potential in vivo. Methods: MTDH and PBGD (control) genes expression were measured by reverse transcription-quantitativepolymerase chain reaction assay using Universal Probe Library in cancerous and non-cancerous cell lines. Results: MTDH gene expression analysis showed a decrease in colorectal cancer cell lines (Caco2, HT29)compared to non-cancerous cells lines (VH10, VH25, Hek293). The mean level of the MTDH mRNA expression,normalized in relation to the reference gene PBGD, increased in the prostate cancer cell linesas follows: PC3 (0.62 ± 0.07), PC3M (1.02 ± 0.17), PC3MPro4 (1.20 ± 0.22), and reached the highestvalue in PC3M4 (1.86 ± 0.48). In VH10, the expression of this gene was at 1.0 ± 0.07. Conclusions: Our MTDH gene expression data are consistent with Mtdh protein expression analyzed inThe Human Protein Atlas (HPA). Increasing MTDH expression is a promising prognostic factor

The GDAP1 p.Glu222Lys Variant-Weak Pathogenic Effect, Cumulative Effect of Weak Sequence Variants, or Synergy of Both Factors?

Charcot–Marie–Tooth disorders (CMT) represent a highly heterogeneous group of diseases of the peripheral nervous system in which more than 100 genes are involved. In some CMT patients, a few weak sequence variants toward other CMT genes are detected instead of one leading CMT mutation. Thus, the presence of a few variants in different CMT-associated genes raises the question concerning the pathogenic status of one of them. In this study, we aimed to analyze the pathogenic effect of c.664G>A, p.Glu222Lys variant in the GDAP1 gene, whose mutations are known to be causative for CMT type 4A (CMT4A). Due to low penetrance and a rare occurrence limited to five patients from two Polish families affected by the CMT phenotype, there is doubt as to whether we are dealing with real pathogenic mutation. Thus, we aimed to study the pathogenic effect of the c.664G>A, p.Glu222Lys variant in its natural environment, i.e., the neuronal SH-SY5Y cell line. Additionally, we have checked the pathogenic status of p.Glu222Lys in the broader context of the whole exome. We also have analyzed the impact of GDAP1 gene mutations on the morphology of the transfected cells. Despite the use of several tests to determine the pathogenicity of the p.Glu222Lys variant, we cannot point to one that would definitively solve the problem of pathogenici

Andersen-Tawil syndrome: report of 3 novel mutations and high risk of symptomatic cardiac involvement.

IntroductionAndersen-Tawil syndrome (ATS) is a potassium channelopathy affecting cardiac and skeletal muscle. Periodic paralysis is a presenting symptom in some patients, whereas, in others, symptomatic arrhythmias or prolongation of QT in echocardiographic recordings will lead to diagnosis of ATS. Striking intrafamilial variability of expression of KCNJ2 mutations and rarity of the syndrome may lead to misdiagnosis.MethodsWe report 15 patients from 8 Polish families with ATS, including 3 with novel KCNJ2 mutations.ResultsAll patients had dysmorphic features; periodic paralysis affected males more frequently than females (80% vs. 20%), and most attacks were normokalemic. Two patients (with T75M and T309I mutations) had aborted sudden cardiac death. An implantable cardioverter-defibrillator was utilized in 40% of cases.ConclusionsKCNJ2 mutations cause a variable phenotype, with dysmorphic features seen in all patients studied, a high penetrance of periodic paralysis in males and ventricular arrhythmia with a risk of sudden cardiac death

A Yeast-Based Model for Hereditary Motor and Sensory Neuropathies: A Simple System for Complex, Heterogeneous Diseases

Charcot–Marie–Tooth (CMT) disease encompasses a group of rare disorders that are characterized by similar clinical manifestations and a high genetic heterogeneity. Such excessive diversity presents many problems. Firstly, it makes a proper genetic diagnosis much more difficult and, even when using the most advanced tools, does not guarantee that the cause of the disease will be revealed. Secondly, the molecular mechanisms underlying the observed symptoms are extremely diverse and are probably different for most of the disease subtypes. Finally, there is no possibility of finding one efficient cure for all, or even the majority of CMT diseases. Every subtype of CMT needs an individual approach backed up by its own research field. Thus, it is little surprise that our knowledge of CMT disease as a whole is selective and therapeutic approaches are limited. There is an urgent need to develop new CMT models to fill the gaps. In this review, we discuss the advantages and disadvantages of yeast as a model system in which to study CMT diseases. We show how this single-cell organism may be used to discriminate between pathogenic variants, to uncover the mechanism of pathogenesis, and to discover new therapies for CMT disease

All-wurtzite (In,Ga)As-(Ga,Mn)As core-shell nanowires grown by molecular beam epitaxy

Structural and magnetic properties of (In,Ga)As-(Ga,Mn)As core-shell nanowires grown by molecular beam epitaxy on GaAs(111)B substrate with gold catalyst have been investigated.(In,Ga)As core nanowires were grown at high temperature (500 {\deg}C) whereas (Ga,Mn)As shells were deposited on the {1-100} side facets of the cores at much lower temperature (220 {\deg}C). High resolution transmission electron microscopy images and high spectral resolution Raman scattering data show that both the cores and the shells of the nanowires have wurtzite crystalline structure. Scanning and transmission electron microscopy observations show smooth (Ga,Mn)As shells containing 5% of Mn epitaxially deposited on (In,Ga)As cores containing about 10% of In, without any misfit dislocations at the core-shell interface. With the In content in the (In,Ga)As cores larger than 5% the (In,Ga)As lattice parameter is higher than that of (Ga,Mn)As and the shell is in the tensile strain state. Elaborated magnetic studies indicate the presence of ferromagnetic coupling in (Ga,Mn)As shells at the temperatures in excess of 33 K. This coupling is maintained only in separated mesoscopic volumes resulting in an overall superparamagnetic behavior which gets blocked below ~17 K.Comment: 37 pages, 8 figure

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The alignment used for the calculations of the double-domain sequences tree. (FASTA 53 kb