Exosomes are secreted organelles that have the same topology as the cell and bud outward (outward is defined as away from the cytoplasm) from endosome membranes or endosome-like domains of plasma membrane. Here we describe an exosomal protein-sorting pathway in Jurkat T cells that selects cargo proteins on the basis of both higher-order oligomerization (the oligomerization of oligomers) and plasma membrane association, acts on proteins seemingly without regard to their function, sequence, topology, or mechanism of membrane association, and appears to operate independently of class E vacuolar protein-sorting (VPS) function. We also show that higher-order oligomerization is sufficient to target plasma membrane proteins to HIV virus–like particles, that diverse Gag proteins possess exosomal-sorting information, and that higher-order oligomerization is a primary determinant of HIV Gag budding/exosomal sorting. In addition, we provide evidence that both the HIV late domain and class E VPS function promote HIV budding by unexpectedly complex, seemingly indirect mechanisms. These results support the hypothesis that HIV and other retroviruses are generated by a normal, nonviral pathway of exosome biogenesis.
We identify and characterize an inhibitory budding signal that acts dominantly to block the budding of otherwise budding-competent proteins, both viral and nonviral, and impairs the budding of several classic, budding-deficient HIV mutants. These findings expand our understanding of EMV biogenesis and resolve a number of previously paradoxical observations regarding the budding of HIV.
e Salmonellosis is a major global foodborne infection, and strains that are resistant to a great variety of antibiotics have become a major public health concern. The aim of this study was to identify genes conferring resistance to fluoroquinolones and extendedspectrum -lactams in nontyphoidal Salmonella (NTS) from patients and food-producing animals in China. In total, 133 and 21 NTS isolates from animals and humans, respectively, exhibiting concurrent resistance to ciprofloxacin and cefotaxime were cultured independently from 2009 to ϳ2013. All of the isolates were identified, serotyped, and subjected to antimicrobial susceptibility testing. Importantly, the isolates with concurrent resistance to ciprofloxacin and cefotaxime all were confirmed as S. enterica serovar Indiana. The presence of fluoroquinolone resistance genes and extended-spectrum -lactamases (ESBLs) was established by PCR and DNA sequencing. The occurrence and diversity of different genes conferring fluoroquinolone resistance [qepA, oqxAB, and aac(6=)-Ib-cr] with mutations in topoisomerase-encoding genes (gyrA and parC) and several ESBLs (including CTX-M-65, CTX-M-27, CTX-M-15, CTX-M-14, and CTX-M-14/CTX-M-15) were noteworthy. Genes located on mobile genetic elements were identified by conjugation and transformation. Pulsed-field gel electrophoresis, used to determine the genetic relationships between these isolates, generated 91 pulsotypes from 133 chicken isolates and 17 pulsotypes from the 21 clinical isolates that showed considerable diversity. Analysis of the pulsotypes obtained with the isolates showed some clones appeared to have existed for several years and had been disseminating between humans and food-producing animals. This study highlights the emergence of ciprofloxacin-and cefotaxime-resistant S. enterica serovar Indiana, posing a threat to public health.
Integrin, beta-like 1 (ITGBL1), is a β-integrin-related extracellular matrix protein which contains ten EGF-like repeats domain. Surprisingly, we screen Oncomine Database and found that ITGBL1 is more commonly downregulated in non-small cell lung cancer (NSCLC) tissues, and the result reminds us to explore its significance in NSCLC. Thus, we retrieved DRUGSURV Database and found that downregulated ITGBL1 predicts a poor prognosis of patients. These results provided us the clues that ITGBL1 might be a tumor suppressor in NSCLC. However, the biological functions of ITGBL1 have not been reported to date. In the current study, we surprisingly found that knockdown of ITGBL1 in NSCLC cell lines could promote cancer cell migration and invasion. Furthermore, recombinant ITGBL1 protein-treated cancer cell could inhibit cell migration and invasion. These results suggested that ITGBL1 plays a suppressive role in NSCLC progression. We further found that the downregulation of ITGBL1 might result from highly expressed miR-576-5p in NSCLC tissues, and the activity of Wnt/PCP signaling was enhanced when the level of ITGBL1 was inhibited. In conclusion, our results suggest that ITGBL1 is a novel tumor suppressor in NSCLC progression.
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