2010N1213

Sudo san: Science 5972, 5973, 5986, 5987, 5989 and 5990

1) 5986 p1698: "Control of membrane protein topology by a single C-terminal residue"
They found that the membrane orientation of the 4-transmembrane domains, dual-topology protein, EmrE could alternate its topology either its N terminus located inside or outside, just by adding a single positively charged residue in various locations throughout the protein. A C-terminal His-tag was effective: N-terminal-in topology was favored when longer His-tag was added at its C-terminus.

2) 5973 p1638: "Shaping development of autophagy inhibitiors with the structure of the lipid kinase Vps34" This paper showed the crystal structure of Vps34, suggesting the reason that specific inhibitors of this class of P13K have proven elusive. Vps34 appears to alternate between a closed cytosolic form and an open form on the membrane.

Yohko san: EMBO Volume 29 issue 17 and EMBO volume 29 issue 18

1) #17 2859, 2875, 2888:
These papers identified Mdm35, which is intra-mitochondrial acceptor protein. Mdm35 and Ups proteins form stable complex in the inter membrane space (IMS). Mdm35, which is present in the IMS in much larger amounts than Ups proteins, functions as intra-mitochondrial complex partner of Ups1 and Ups2. Ups proteins may reach the IMS by sequential interactions with the outer membrane receptors Tom20 and Tom22 on the mitochondrial surface and Mdm35.

2) #18 p3068: "Cell cycle coordination and regulation of bacterial chromosome segregation dynamics by polarly localized proteins"
They studied in Caulobacter crescentus that the polarity factor TipN regulates the directional motion and overall translocation speed of the parS/ParB partition complex by interacting with ParA at the new pole. A mechanistic framework for adapting a self-organizing oscillator to create motion suitable for chromosome segregation are been studied. pars/ParB/ParA partitioning systems may require extrinsic regulation to prevent back-and-forth motions.

Wariishi san PNAS Vol. 107 No. 29, 31

1) #29 p12846: "Asymmetry in the clockwise and counterclockwise rotation of the bacterial flagellar motor" They measure the torque-speed relationship for cells that express large amounts of CheY and only spin their motor clockwise (CW) direction. CCW rotation might be optimized for runs, with higher speeds increasing the ability of cells to sense spatial gradients, whereas CW rotation might be optimized for tumbles, where the object is to change cell trajectories.

2) #31 p13866: "Coexistence of two adamantane binding sites in the influenza A M2 ion channel" The influentza A virus contains a proton-selective ion channel (M2). The amantadine drug is capable of binding to M2 with two different affinities. The high affinity binding site corresponds to the M2 ion channel pore whereas the low-affinity binding site can be attributed to the lipid face of the pore.

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