The plasma membrane of eukaryotic cells is organized into lipid and protein microdomains, whose assembly mechanisms and functions are incompletely understood. We demonstrate that proteins in the nephrin/Nck/N-WASP actin-regulatory pathway cluster into micron-scale domains at the basal plasma membrane upon triggered phosphorylation of transmembrane protein nephrin. The domains are persistent but readily exchange components with their surroundings, and their formation is dependent on the number of Nck SH3 domains, suggesting they are phase separated polymers assembled through multivalent interactions among the three proteins. The domains form independent of the actin cytoskeleton, but acto-myosin contractility induces their rapid lateral movement. Nephrin phosphorylation induces larger clusters at the cell periphery, which are associated with extensive actin assembly and dense filopodia. Our studies illustrate how multivalent interactions between proteins at the plasma membrane can produce micron-scale organization of signaling molecules, and how the resulting clusters can both respond to and control the actin cytoskeleton.
This study examined the α-glucosidase inhibitory, and apoptosis- and anti-muscular-related factors of goat meat extracts from forelegs, hind legs, loin, and ribs. The goat meat extracts were evaluated for their α-glucosidase inhibitory activity. The gene and protein expression levels of Bcl-2-associated X (bax), p53, and p21 were examined by reverse transcription polymerase chain reaction (RT-PCR) and immunoblotting in AGS and HT-29 cells. The expression levels of Atrogin-1 and MHC1b were examined by RT-PCR in C2C12 myoblasts, and the expression levels of Atrogin-1, muscle atrophy F-box (MAFbx), muscle RING-finger protein-1 (MuRF-1), and myosin heavy chain-7 were investigated by immunoblotting. α-Glucosidase inhibitory activity was higher in ethanol extract than in hydrous and hot water extracts. BAX and p53 expression levels were higher (p<0.05) in AGS cells treated with goat meat extract than those of cells treated with no goat meat extract. In HT-29 cells, the protein expression levels of BAX, p53, and p21 were higher (p<0.05) in the cells treated with goat meat extract than those of cells not treated with goat meat extract. In dexamethasone-treated C2C12 cells, goat meat extract treatment lower (p<0.05) the expression of Atrogin-1 and lower (p<0.05) the expression of MAFbx and MuRF-1. The results of the present study indicate that goat meat extracts have α-glucosidase inhibitory activity in vitro. In addition, apoptosis was induced in AGS cells and HT-29 cells treated with goat meat extract, and anti-muscular atrophy activity was also observed in C2C12 cells treated with goat meat extract.
An aerobic and Gram-stain-negative bacterial strain, designated UKS-15T, was isolated from lake water in the Republic of Korea. Results of 16S rRNA gene sequence and phylogenetic analyses indicated that the novel isolate belongs to the genus Lysobacter and was most closely related to Lysobacter xinjiangensis RCML-52T (98.0 %), Lysobacter mobilis 9 NM-14T (97.4 %) and Lysobacter humi FJY8T (97.2 %). The DNA G+C content was 69.1 mol%. Strain UKS-15T possessed ubiquinone-8 (Q-8) as the sole respiratory quinone and the fatty acid profile comprised iso-C15 : 0, iso-C17 : 0 and summed feature 9 (iso-C17 : 1 ω9c and/or C16 : 0 10-methyl) as its major components. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and one unidentified aminophospholipid. Moreover, the physiological and biochemical results and low level of DNA-DNA relatedness (<22.0 %) allowed the phenotypic and genotypic differentiation of strain UKS-15T from other Lysobacter species. Therefore, on the basis of the data from this polyphasic taxonomic study, strain UKS-15T should represent a novel species of the genus Lysobacter, for which the name Lysobacter lacus sp. nov. is proposed. The type strain is UKS-15T (=JCM 30983T=KACC 18719T).