We report more than 1400 proteins of the secretory-pathway proteome and provide spatial information on the relative presence of each protein in the rough and smooth ER Golgi cisternae and Golgi-derived COPI vesicles. The data support a role for COPI vesicles in recycling and cisternal maturation, showing that Golgi-resident proteins are present at a higher concentration than secretory cargo. Of the 1400 proteins, 345 were identified as previously uncharacterized. Of these, 230 had their subcellular location deduced by proteomics. This study provides a comprehensive catalog of the ER and Golgi proteomes with insight into their identity and function.

The accumulation of cytosolic lipid droplets in muscle and liver cells has been linked to the development of insulin resistance and type 2 diabetes. Such droplets are formed as small structures that increase in size through fusion, a process that is dependent on intact microtubules and the motor protein dynein. Approximately 15% of all droplets are involved in fusion processes at a given time. Here, we show that lipid droplets are associated with proteins involved in fusion processes in the cell: NSF (N-ethylmaleimide-sensitive-factor), alpha-SNAP (soluble NSF attachment protein) and the SNAREs (SNAP receptors), SNAP23 (synaptosomal-associated protein of 23 kDa), syntaxin-5 and VAMP4 (vesicle-associated membrane protein 4). Knockdown of the genes for SNAP23, syntaxin-5 or VAMP4, or microinjection of a dominant-negative mutant of alpha-SNAP, decreases the rate of fusion and the size of the lipid droplets. Thus, the SNARE system seems to have an important role in lipid droplet fusion. We also show that oleic acid treatment decreases the insulin sensitivity of heart muscle cells, and this sensitivity is completely restored by transfection with SNAP23. Thus, SNAP23 might be a link between insulin sensitivity and the inflow of fatty acids to the cell.

MXenes, a young family of two-dimensional (2D) transition metal carbides/nitrides, show great potential in electrochemical energy storage applications. Herein, a high performance ultra-thin flexible solid-state supercapacitor is demonstrated based on a Mo1.33C MXene with vacancyordering in an aligned layer structure MXene/PEDOT:PSS composite film post-treated with concentrated H2SO4. The flexible solid-state supercapacitor delivers a maximum capacitance of 568 F cm-3 , an ultrahigh energy density of 33.2 mWh cm-3 and a power density of 19470 mW cm-3. The Mo1.33C MXene/PEDOT:PSS composite film shows a reduction in resistance upon H2SO4 treatment, a higher capacitance (1310 F cm-3) and improved rate-capabilities than both pristine Mo1.33C MXene and the non-treated Mo1.33C/PEDOT:PSS composite films. The enhanced capacitance and stability are attributed to the synergistic effect of increased interlayer

We have investigated the role for diacylglycerol (DAG) in membrane bud formation in the Golgi apparatus. Addition of propranolol to specifically inhibit phosphatidate phosphohydrolase (PAP), an enzyme responsible for converting phosphatidic acid into DAG, effectively prevents formation of membrane buds. The effect of PAP inhibition on Golgi membranes is rapid and occurs within 3 min. Removal of the PAP inhibitor then results in a rapid burst of buds, vesicles, and tubules that peaks within 2 min. The inability to form buds in the presence of propranolol does not appear to be correlated with a loss of ARFGAP1 from Golgi membranes, as knockdown of ARFGAP1 by RNA interference has little or no effect on actual bud formation. Rather, knockdown of ARFGAP1 results in an increase in membrane buds and a decrease of vesicles and tubules suggesting it functions in the late stages of scission. How DAG promotes bud formation is discussed. INTRODUCTIONFormation of buds to generate intracellular transport vesicles from membranes such as Golgi cisternae involves both coat binding and local lipid conversion (for reviews and theoretical models, see Kirchhausen, 2000;Shemesh et al., 2003;Weiss and Nilsson, 2003;Bethune et al., 2006). For COPI vesicles, formation of buds is initiated by the small GTPase ARF1 (ADP-ribosylation factor 1) which, in its GTPconferred conformation, drives coatomer recruitment from the cytosol to both Golgi and pre-Golgi membranes (Palmer et al., 1993). Indeed, ARF1 and coatomer are sufficient for both bud and vesicle formation as evidenced in in vitro experiments using liposomes forming coated vesicles in a controlled manner (Spang et al., 1998). Addition of ARF-GAP1, a GTPase-activating protein for ARF1, then yielded uncoated vesicles of the expected size of ϳ50-60 nm in diameter (Reinhard et al., 2003).The situation in biological membranes is likely more refined involving additional as well as alternative components to promote or prevent vesicle formation such that Golgi function is maintained. Here, both ARF1 and ARFGAP1 have been implicated in vesicle formation through direct or indirect modulation of lipid synthesis such that bud formation and membrane fission are promoted. For example, ARF1 stimulates the production of phosphatidic acid (PA) from phosphatidylcholine (PC; Brown et al., 1993;Cockcroft et al., 1994) through the activation of phospholipase D (PLD) in a nucleotide (GTP)-specific manner Houle et al., 1995;Ktistakis et al., 1995). Such ARF1-mediated PLD stimulation results in an increased vesicle production (Ktistakis et al., 1996;Chen et al., 1997). This ability of ARF1 to stimulate lipid formation in the Golgi apparatus offers a possibility to mechanistically link lipid conversion with coat recruitment. PA may also be converted to diacylglycerol (DAG) and the ratio between DAG and PC seems to influence protein transport through the Golgi apparatus in yeast (Rivas et al., 1999). PA can also be synthesized from lysophosphatidic acid (LPA) by a LPA acyltransferase-dependent pathway through...

Sir2 is a central regulator of yeast aging and its deficiency increases daughter cell inheritance of stress- and aging-induced misfolded proteins deposited in aggregates and inclusion bodies. Here, by quantifying traits predicted to affect aggregate inheritance in a passive manner, we found that a passive diffusion model cannot explain Sir2-dependent failures in mother-biased segregation of either the small aggregates formed by the misfolded Huntingtin, Htt103Q, disease protein or heat-induced Hsp104-associated aggregates. Instead, we found that the genetic interaction network of SIR2 comprises specific essential genes required for mother-biased segregation including those encoding components of the actin cytoskeleton, the actin-associated myosin V motor protein Myo2, and the actin organization protein calmodulin, Cmd1. Co-staining with Hsp104-GFP demonstrated that misfolded Htt103Q is sequestered into small aggregates, akin to stress foci formed upon heat stress, that fail to coalesce into inclusion bodies. Importantly, these Htt103Q foci, as well as the ATPase-defective Hsp104Y662A-associated structures previously shown to be stable stress foci, co-localized with Cmd1 and Myo2-enriched structures and super-resolution 3-D microscopy demonstrated that they are associated with actin cables. Moreover, we found that Hsp42 is required for formation of heat-induced Hsp104Y662A foci but not Htt103Q foci suggesting that the routes employed for foci formation are not identical. In addition to genes involved in actin-dependent processes, SIR2-interactors required for asymmetrical inheritance of Htt103Q and heat-induced aggregates encode essential sec genes involved in ER-to-Golgi trafficking/ER homeostasis.

Discovered in 1909 by Retzius and described mainly by morphology, the cytoplasmic droplet of sperm (renamed here the Hermes body) is conserved among all mammalian species but largely undefined at the molecular level. Tandem mass spectrometry of the isolated Hermes body from rat epididymal sperm characterized 1511 proteins, 43 of which were localized to the structure in situ by light microscopy and two by quantitative electron microscopy localization. Glucose transporter 3 (GLUT-3) glycolytic enzymes, selected membrane traffic and cytoskeletal proteins were highly abundant and concentrated in the Hermes body. By electron microscope gold antibody labelling, the Golgi trafficking protein TMED7/p27 localized to unstacked flattened cisternae of the Hermes body, as did GLUT-3, the most abundant protein. Its biogenesis was deduced through the mapping of protein expression for all 43 proteins during male germ cell differentiation in the testis. It is at the terminal step 19 of spermiogenesis that the 43 characteristic proteins accumulated in the nascent Hermes body.

In SNOLL the injection procedures are performed separately, but both lesion and SNs are removed together; axillary dissection is performed if the SN is positive, thus definitive treatment of malignant non-palpable lesions occurs in a single surgical session.

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