Longitudinal analysis of the faecal microbiome in pigs fed Cyberlindnera jadinii yeast as a protein source during the weanling period followed by a rapeseed‑ and faba bean‑based grower‑finisher diet

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Rab7b modulates autophagic flux by interacting with Atg4B

Autophagy (macroautophagy) is a highly conserved eukaryotic degradation pathway in which cytosolic components and organelles are sequestered by specialized autophagic membranes and degraded through the lysosomal system. The autophagic pathway maintains basal cellular homeostasis and helps cells adapt during stress; thus, defects in autophagy can cause detrimental effects. It is therefore crucial that autophagy is properly regulated. In this study, we show that the cysteine protease Atg4B, a key enzyme in autophagy that cleaves LC3, is an interactor of the small GTPase Rab7b. Indeed, Atg4B interacts and co‐localizes with Rab7b on vesicles. Depletion of Rab7b increases autophagic flux as indicated by the increased size of autophagic structures as well as the magnitude of macroautophagic sequestration and degradation. Importantly, we demonstrate that Rab7b regulates LC3 processing by modulating Atg4B activity. Taken together, our findings reveal Rab7b as a novel negative regulator of autophagy through its interaction with Atg4B

Rab and Arf proteins at the crossroad between membrane transport and cytoskeleton dynamics

The intracellular movement and positioning of organelles and vesicles is mediated by the cytoskeleton and molecular motors. Small GTPases like Rab and Arf proteins are main regulators of intracellular transport by connecting membranes to cytoskeleton motors or adaptors. However, it is becoming clear that interactions between these small GTPases and the cytoskeleton are important not only for the regulation of membrane transport. In this review, we will cover our current understanding of the mechanisms underlying the connection between Rab and Arf GTPases and the cytoskeleton, with special emphasis on the double role of these interactions, not only in membrane trafficking but also in membrane and cytoskeleton remodeling. Furthermore, we will highlight the most recent findings about the fine control mechanisms of crosstalk between different members of Rab, Arf, and Rho families of small GTPases in the regulation of cytoskeleton organization

PAPST1 regulates sulfation of heparan sulfate proteoglycans in epithelial MDCK II cells.

Proteoglycan (PG) sulfation depends on activated nucleotide sulfate, 3'-phosphoadenosine-5'-phosphosulfate (PAPS). Transporters in the Golgi membrane translocate PAPS from the cytoplasm into the organelle lumen where PG sulfation occurs. Silencing of PAPS transporter (PAPST) 1 in epithelial MDCK cells reduced PAPS uptake into Golgi vesicles. Surprisingly, at the same time sulfation of heparan sulfate (HS) was stimulated. The effect was pathway specific in polarized epithelial cells. Basolaterally secreted PGs displayed an altered HS sulfation pattern and increased growth factor binding capacity. In contrast, the sulfation pattern of apically secreted PGs was unchanged while the secretion was reduced. Regulation of PAPST1 allows epithelial cells to prioritize between PG sulfation in the apical and basolateral secretory routes at the level of the Golgi apparatus. This provides sulfation patterns that ensure PG functions at the extracellular level, such as growth factor binding

Alumina scale composition and growth rate in distribution pipes

Scaling in distribution pipes for secondary alumina is a major issue in aluminium smelters. The scale is formed inside the distribution pipes, and gradually reduces the cross section that is available for alumina transport. The scale cannot be removed without dismantling the transport pipes and using chemical and/or mechanical treatments. This leads to interruptions in normal operation, requires additional labour, and a stock of additional pipe sections. To get a better understanding of the scale formation mechanisms, the rate of scale growth was monitored by acoustic measurements in a transport pipe section at an aluminium producing plant over a period of several months. Correlation between growth rate, and recorded parameters from the associated pots, fume treatment system and meteorological data were studied. In addition, samples from the actual scale were examined by SEM, TEM and AFM to investigate the microstructure and chemical composition

Rab6 regulates cell migration and invasion by recruiting Cdc42 and modulating its activity.

Rab proteins are master regulators of intracellular membrane trafficking, but they also contribute to cell division, signaling, polarization, and migration. The majority of the works describing the mechanisms used by Rab proteins to regulate cell motility involve intracellular transport of key molecules important for migration. Interestingly, a few studies indicate that Rabs can modulate the activity of Rho GTPases, important regulators for the cytoskeleton rearrangements, but the mechanisms behind this crosstalk are still poorly understood. In this work, we identify Rab6 as a negative regulator of cell migration in vitro and in vivo. We show that the loss of Rab6 promotes formation of actin protrusions and influences actomyosin dynamics by upregulating Cdc42 activity and downregulating myosin II phosphorylation. We further provide the molecular mechanism behind this regulation demonstrating that Rab6 interacts with both Cdc42 and Trio, a GEF for Cdc42. In sum, our results uncover a mechanism used by Rab proteins to ensure spatial regulation of Rho GTPase activity for coordination of cytoskeleton rearrangements required in migrating cells

Replacing soybean meal with rapeseed meal and faba beans in a growing-finishing pig diet: Effect on growth performance, meat quality and metabolite changes

Rapeseed meal and faba beans (RSM/FB) can serve as an alternative to imported soybean meal 35 (SBM). In this study, forty Norwegian crossbred ([Landrace x Yorkshire] x Duroc) growing36 finishing pigs (108.7±4.2 kg final BW) were fed a diet with either SBM or RSM/FB as protein 37 sources. RSM/FB increased feed conversion ratio (P=0.04) in the finishing period, reduced 38 lightness (P=0.04) and yellowness (P=0.004) of meat, changed amounts of individual fatty acids, 39 but not of total SFA, MUFA and PUFA. Importantly, RSM/FB reduced the glucose level (P < 40 0.05) in meat. Lower pyroglutamic acid (P = 0.06) in RSM/FB indicate lower oxidative stress in 41 pre-rigor muscle cell. Increased abundance of free amino acids, sweet tasting metabolites, reduced 42 warmed-over flavor and flavor attributes indicated desirable properties of RSM/FB meat. To 43 conclude, RSM/FB in pig diet supported a high growth performance and carcass quality 44 comparable to SBM and had a positive effect on meat quality.acceptedVersio

Rab18 regulates focal adhesion dynamics by interacting with kinectin-1 at the endoplasmic reticulum

The members of the Rab family of small GTPases are molecular switches that regulate distinct steps in different membrane traffic pathways. In addition to this canonical function, Rabs can play a role in other processes, such as cell adhesion and motility. Here, we reveal the role of the small GTPase Rab18 as a positive regulator of directional migration in chemotaxis, and the underlying mechanism. We show that knockdown of Rab18 reduces the size of focal adhesions (FAs) and influences their dynamics. Furthermore, we found that Rab18, by directly interacting with the endoplasmic reticulum (ER)-resident protein kinectin-1, controls the anterograde kinesin-1–dependent transport of the ER required for the maturation of nascent FAs and protrusion orientation toward a chemoattractant. Altogether, our data support a model in which Rab18 regulates kinectin-1 transport toward the cell surface to form ER–FA contacts, thus promoting FA growth and cell migration during chemotaxi