Secreted protein acidic and rich in cysteine (SPARC) induces lipotoxicity in neuroblastoma by regulating transport of albumin complexed with fatty acids.

SPARC is a matrix protein that mediates interactions between cells and the microenvironment. In cancer, SPARC may either promote or inhibit tumor growth depending upon the tumor type. In neuroblastoma, SPARC is expressed in the stromal Schwannian cells and functions as a tumor suppressor.

A High-Throughput Cell-Based Screen Identified a 2-[(E)-2-Phenylvinyl]-8-Quinolinol Core Structure That Activates p53.

p53 function is frequently inhibited in cancer either through mutations or by increased degradation via MDM2 and/or E6AP E3-ubiquitin ligases. Most agents that restore p53 expression act by binding MDM2 or E6AP to prevent p53 degradation. However, fewer compounds directly bind to and activate p53.

A novel single-chain antibody redirects adenovirus to IL13Rα2-expressing brain tumors.

The generation of a targeting agent that strictly binds to IL13Rα2 will significantly expand the therapeutic potential for the treatment of IL13Rα2-expressing cancers. In order to fulfill this goal, we generated a single-chain antibody (scFv47) from our parental IL13Rα2 monoclonal antibody and tested its binding properties. Furthermore, to demonstrate the potential therapeutic applicability of scFv47, we engineered an adenovirus by incorporating scFv47 as the targeting moiety in the viral fiber and characterized its properties in vitro and in vivo.

Characterization and immunotherapeutic implications for a novel antibody targeting interleukin (IL)-13 receptor α2.

The high affinity interleukin-13 receptor α2 (IL13Rα2) is selectively expressed at a high frequency by glioblastoma multiforme (GBM) as well as several other tumor types. One approach for targeting this tumor-specific receptor utilizes the cognate ligand, IL-13, conjugated to cytotoxic molecules. However, this approach lacks specificity because the lower affinity receptor for IL-13, IL13Rα1, is widely expressed by normal tissues.

A Bacillus anthracis S-layer homology protein that binds heme and mediates heme delivery to IsdC.

The sequestration of iron by mammalian hosts represents a significant obstacle to the establishment of a bacterial infection. In response, pathogenic bacteria have evolved mechanisms to acquire iron from host heme. Bacillus anthracis, the causative agent of anthrax, utilizes secreted hemophores to scavenge heme from host hemoglobin, thereby facilitating iron acquisition from extracellular heme pools and delivery to iron-regulated surface determinant (Isd) proteins covalently attached to the cell wall.

Cyclic AMP-mediated endocytosis of intestinal epithelial NHE3 requires binding to synaptotagmin 1.

The apical membrane Na(+)-H(+) exchanger (NHE)3 is regulated by cAMP-dependent phosphorylation, which inhibits its activity through membrane endocytosis. The clathrin complex adaptor protein synaptotagmin 1 (Syt 1) appears to be essential to this process, but little is known about its expression in intestinal epithelial cells or interaction with NHE3. The intestinal epithelial expression and apical location of Syt 1 were determined by Syt 1 mRNA profiling and immunolocalization.

Heme transfer to the bacterial cell envelope occurs via a secreted hemophore in the Gram-positive pathogen Bacillus anthracis.

To initiate and sustain an infection in mammals, bacterial pathogens must acquire host iron. However, the host's compartmentalization of large amounts of iron in heme, which is bound primarily by hemoglobin in red blood cells, acts as a barrier to bacterial iron assimilation. Bacillus anthracis, the causative agent of the disease anthrax, secretes two NEAT (near iron transporter) proteins, IsdX1 and IsdX2, which scavenge heme from host hemoglobin and promote growth under low iron conditions.

Pentameric assembly of potassium channel tetramerization domain-containing protein 5.

We report the X-ray crystal structure of human potassium channel tetramerization domain-containing protein 5 (KCTD5), the first member of the family to be so characterized. Four findings were unexpected. First, the structure reveals assemblies of five subunits while tetramers were anticipated; pentameric stoichiometry is observed also in solution by scanning transmission electron microscopy mass analysis and analytical ultracentrifugation.

Protein-protein docking and analysis reveal that two homologous bacterial adenylyl cyclase toxins interact with calmodulin differently.

Calmodulin (CaM), a eukaryotic calcium sensor that regulates diverse biological activities, consists of N- and C-terminal globular domains (N-CaM and C-CaM, respectively). CaM serves as the activator of CyaA, a 188-kDa adenylyl cyclase toxin secreted by Bordetella pertussis, which is the etiologic agent for whooping cough. Upon insertion of the N-terminal adenylyl cyclase domain (ACD) of CyaA to its targeted eukaryotic cells, CaM binds to this domain tightly ( approximately 200 pm affinity).

Two mechanistically distinct forms of endocytosis in adrenal chromaffin cells: Differential effects of SH3 domains and amphiphysin antagonism.

We previously identified two forms of endocytosis using capacitance measurements in chromaffin cells: rapid endocytosis (RE), dynamin-1 dependent but clathrin-independent and slow endocytosis (SE), dynamin-2 and clathrin-dependent. Various recombinant SH3 domains that interact with the proline-rich domain of dynamin were introduced into single cells via the patch pipette. GST-SH3 domains of amphiphysin-1, intersectin-IC, and endophilin-I inhibited SE but had no effect on RE.

Conformational changes in dynamin on GTP binding and oligomerization reported by intrinsic and extrinsic fluorescence.

The effects of guanine nucleotides on the intrinsic and extrinsic fluorescence properties of dynamin were assessed. The intrinsic Trp (tryptophan) fluorescence spectra of purified recombinant dynamin-1 and -2 were very similar, with a maximum at 332 nm. Collisional quenching by KI was weak (approximately 30%), suggesting that the majority of Trp residues are buried.

Kinetics of Src homology 3 domain association with the proline-rich domain of dynamins: specificity, occlusion, and the effects of phosphorylation.

Dynamin function is mediated in part through association of its proline-rich domain (PRD) with the Src homology 3 (SH3) domains of several putative binding proteins. To assess the specificity and kinetics of this process, we undertook surface plasmon resonance studies of the interaction between isolated PRDs of dynamin-1 and -2 and several purified SH3 domains. Glutathione S-transferase-linked SH3 domains bound with high affinity (K(D) approximately 10 nm to 1 microm) to both dynamin-1 and -2.