ErbB4 reduces synaptic GABAA currents independent of its receptor tyrosine kinase activity.

ErbB4 signaling in the central nervous system is implicated in neuropsychiatric disorders and epilepsy. In cortical tissue, ErbB4 associates with excitatory synapses located on inhibitory interneurons. However, biochemical and histological data described herein demonstrate that the vast majority of ErbB4 is extrasynaptic and detergent-soluble.

A coordinated proteomic approach for identifying proteins that interact with the E. coli ribosomal protein S12.

The bacterial ribosomal protein S12 contains a universally conserved D88 residue on a loop region thought to be critically involved in translation due to its proximal location to the A site of the 30S subunit. While D88 mutants are lethal this residue has been found to be post-translationally modified to β-methylthioaspartic acid, a post-translational modification (PTM) identified in S12 orthologs from several phylogenetically distinct bacteria. In a previous report focused on characterizing this PTM, our results provided evidence that this conserved loop region might be involved in forming multiple proteins-protein interactions ( Strader , M.

A proteomic and transcriptomic approach reveals new insight into beta-methylthiolation of Escherichia coli ribosomal protein S12.

β-methylthiolation is a novel post-translational modification mapping to a universally conserved Asp 88 of the bacterial ribosomal protein S12. This S12 specific modification has been identified on orthologs from multiple bacterial species. The origin and functional significance was investigated with both a proteomic strategy to identify candidate S12 interactors and expression microarrays to search for phenotypes that result from targeted gene knockouts of select candidates.

Huntington's disease protein contributes to RNA-mediated gene silencing through association with Argonaute and P bodies.

Huntington's disease is a dominant autosomal neurodegenerative disorder caused by an expansion of polyglutamines in the huntingtin (Htt) protein, whose cellular function remains controversial. To gain insight into Htt function, we purified epitope-tagged Htt and identified Argonaute as associated proteins. Colocalization studies demonstrated Htt and Ago2 to be present in P bodies, and depletion of Htt showed compromised RNA-mediated gene silencing.

Analysis of TRPC3-interacting proteins by tandem mass spectrometry.

Mammalian transient receptor potential canonical (TRPC) channels are a family of nonspecific cation channels that are activated in response to stimulation of phospholipase C (PLC)-dependent hydrolysis of the membrane lipid phosphatidylinositol 4,5-bisphosphate. Despite extensive studies, the mechanism(s) involved in regulation of mammalian TRPC channels remains unknown. Presence of various protein-interacting domains in TRPC channels have led to the suggestion that they associate with proteins that are involved in their function and regulation.

Composition of the synaptic PSD-95 complex.

Postsynaptic density protein 95 (PSD-95), a specialized scaffold protein with multiple protein interaction domains, forms the backbone of an extensive postsynaptic protein complex that organizes receptors and signal transduction molecules at the synaptic contact zone. Large, detergent-insoluble PSD-95-based postsynaptic complexes can be affinity-purified from conventional PSD fractions using magnetic beads coated with a PSD-95 antibody. In the present study purified PSD-95 complexes were analyzed by LC/MS/MS.

Reexamination of the cysteine residues in glucocerebrosidase.

Glucocerebrosidase, the deficient enzyme in Gaucher disease, catalyzes the cleavage of the beta-glycosidic linkage of glucosylceramide. A previous study on the enzyme identified three disulfide bridges and a single sulfhydryl [Lee, Y., Kinoshita, H.

Alterations in the rat serum proteome during liver injury from acetaminophen exposure.

Changes in the serum proteome were identified during early, fulminant, and recovery phases of liver injury from acetaminophen in the rat. Male F344 rats received a single, noninjury dose or a high, injury-producing dose of acetaminophen for evaluation at 6 to 120 h. Two-dimensional gel electrophoresis of immunodepleted serum separated approximately 800 stained proteins per sample from which differentially expressed proteins were identified by mass spectrometry.

Characterization of the human urinary proteome: a method for high-resolution display of urinary proteins on two-dimensional electrophoresis gels with a yield of nearly 1400 distinct protein spots.

The abundance profile of the human urinary proteome is known to change as a result of diseases or drug toxicities, particularly of those affecting the kidney and the urogenital tract. A consequence of such insults is the ability to identify proteins in urine, which may be useful as quantitative biomarkers. To succeed in discovering them, reproducible urine sample preparation methods and good protein resolution in two-dimensional electrophoresis (2-DE) gels for parallel semiquantitative protein measurements are desirable.

The human serum proteome: display of nearly 3700 chromatographically separated protein spots on two-dimensional electrophoresis gels and identification of 325 distinct proteins.

Plasma, the soluble component of the human blood, is believed to harbor thousands of distinct proteins, which originate from a variety of cells and tissues through either active secretion or leakage from blood cells or tissues. The dynamic range of plasma protein concentrations comprises at least nine orders of magnitude. Proteins involved in coagulation, immune defense, small molecule transport, and protease inhibition, many of them present in high abundance in this body fluid, have been functionally characterized and associated with disease processes.