ROR and RYK extracellular region structures suggest that receptor tyrosine kinases have distinct WNT-recognition modes.

WNTs play key roles in development and disease, signaling through Frizzled (FZD) seven-pass transmembrane receptors and numerous co-receptors including ROR and RYK family receptor tyrosine kinases (RTKs). We describe crystal structures and WNT-binding characteristics of extracellular regions from the Drosophila ROR and RYK orthologs Nrk (neurospecific receptor tyrosine kinase) and Derailed-2 (Drl-2), which bind WNTs though a FZD-related cysteine-rich domain (CRD) and WNT-inhibitory factor (WIF) domain respectively. Our crystal structures suggest that neither Nrk nor Drl-2 can accommodate the acyl chain typically attached to WNTs.

Detecting Protein-Ligand Interaction from Integrated Transient Induced Molecular Electronic Signal (i-TIMES).

Quantitative information about protein-ligand interactions is central to drug discovery. To obtain the quintessential reaction dissociation constant, ideally measurements of reactions should be performed without perturbations by molecular labeling or immobilization. The technique of transient induced molecular electrical signal (TIMES) has provided a promising technique to meet such requirements, and its performance in a microfluidic environment further offers the potential for high throughput and reduced consumption of reagents.

Measuring Electric Charge and Molecular Coverage on Electrode Surface from Transient Induced Molecular Electronic Signal (TIMES).

Charge density and molecular coverage on the surface of electrode play major roles in the science and technology of surface chemistry and biochemical sensing. However, there has been no easy and direct method to characterize these quantities. By extending the method of Transient Induced Molecular Electronic Signal (TIMES) which we have used to measure molecular interactions, we are able to quantify the amount of charge in the double layers at the solution/electrode interface for different buffer strengths, buffer types, and pH values.

Receptor tyrosine kinases with intracellular pseudokinase domains.

As with other groups of protein kinases, approximately 10% of the RTKs (receptor tyrosine kinases) in the human proteome contain intracellular pseudokinases that lack one or more conserved catalytically important residues. These include ErbB3, a member of the EGFR (epidermal growth factor receptor) family, and a series of unconventional Wnt receptors. We showed previously that, despite its reputation as a pseudokinase, the ErbB3 TKD (tyrosine kinase domain) does retain significant, albeit weak, kinase activity.

ErbB3/HER3 intracellular domain is competent to bind ATP and catalyze autophosphorylation.

ErbB3/HER3 is one of four members of the human epidermal growth factor receptor (EGFR/HER) or ErbB receptor tyrosine kinase family. ErbB3 binds neuregulins via its extracellular region and signals primarily by heterodimerizing with ErbB2/HER2/Neu. A recently appreciated role for ErbB3 in resistance of tumor cells to EGFR/ErbB2-targeted therapeutics has made it a focus of attention.

Structural basis for EGFR ligand sequestration by Argos.

Members of the epidermal growth factor receptor (EGFR) or ErbB/HER family and their activating ligands are essential regulators of diverse developmental processes. Inappropriate activation of these receptors is a key feature of many human cancers, and its reversal is an important clinical goal. A natural secreted antagonist of EGFR signalling, called Argos, was identified in Drosophila.

CPG15, a new factor upregulated after ischemic brain injury, contributes to neuronal network re-establishment after glutamate-induced injury.

Candidate plasticity-related gene 15 (cpg15) encodes a protein that regulates dendritic and axonal arbor growth and synaptic maturation. In the present study, we investigated the potential role of CPG15 in regulating the neuronal network re-establishment after ischemic brain injury. In the mouse model with transient global ischemia (TGI), CPG15 transcripts and proteins were determined using RT-PCR and Western blot analyses.