No abstract

Serogroup B Neisseria meningitidis (MenB) is a major cause of severe sepsis and invasive meningococcal disease, which is associated with 5-15% mortality and devastating long-term sequelae. Neisserial adhesin A (NadA), a trimeric autotransporter adhesin (TAA) that acts in adhesion to and invasion of host epithelial cells, is one of the three antigens discovered by genome mining that are part of the MenB vaccine that recently was approved by the European Medicines Agency. Here we present the crystal structure of NadA variant 5 at 2 Å resolution and transmission electron microscopy data for NadA variant 3 that is present in the vaccine. The two variants show similar overall topology with a novel TAA fold predominantly composed of trimeric coiled-coils with three protruding wing-like structures that create an unusual N-terminal head domain. Detailed mapping of the binding site of a bactericidal antibody by hydrogen/deuterium exchange MS shows that a protective conformational epitope is located in the head of NadA. These results provide information that is important for elucidating the biological function and vaccine efficacy of NadA.meningitis | coiled coil | thermostability | hydrogen-deuterium exchange | trimeric autotransporter adhesin

Malignant melanoma is one of the most aggressive human cancers, but the mechanisms governing its metastatic dissemination are not fully understood. Upregulation of miR-214 and ALCAM and the loss of TFAP2 expression have been implicated in this process, with TFAP2 a direct target of miR-214. Here, we link miR-214 and ALCAM as well as identify a core role for miR-214 in organizing melanoma metastasis. miR-214 upregulated ALCAM, acting transcriptionally through TFAP2 and also posttranscriptionally through miR-148b (itself controlled by TFAP2), both negative regulators of ALCAM. We also identified several miR-214-mediated prometastatic functions directly promoted by ALCAM. Silencing ALCAM in miR-214-overexpressing melanoma cells reduced cell migration and invasion without affecting growth or anoikis in vitro, and it also impaired extravasation and metastasis formation in vivo. Conversely, cell migration and extravasation was reduced in miR-214-overexpressing cells by upregulation of either miR-148b or TFAP2. These findings were consistent with patterns of expression of miR-214, ALCAM, and miR-148b in human melanoma specimens. Overall, our results define a pathway involving miR-214, miR-148b, TFAP2, and ALCAM that is critical for establishing distant metastases in melanoma. Cancer Res; 73(13); 4098-111. Ó2013 AACR.

No abstract

Hedgehog signaling is central in embryonic development and tissue regeneration. Disruption of the pathway is linked to genetic diseases and cancer. Binding of the secreted ligand, Sonic hedgehog (ShhN) to its receptor Patched (PTCH1) activates the signaling pathway. Here, we describe a 3.4-Å cryo-EM structure of the human PTCH1 bound to ShhNC24II, a modified hedgehog ligand mimicking its palmitoylated form. The membrane-embedded part of PTCH1 is surrounded by 10 sterol molecules at the inner and outer lipid bilayer portion of the protein. The annular sterols interact at multiple sites with both the sterol-sensing domain (SSD) and the SSD-like domain (SSDL), which are located on opposite sides of PTCH1. The structure reveals a possible route for sterol translocation across the lipid bilayer by PTCH1 and homologous transporters.