Target identification using drug affinity responsive target stability (DARTS).

Identifying the molecular targets for the beneficial or detrimental effects of small-molecule drugs is an important and currently unmet challenge. We have developed a method, drug affinity responsive target stability (DARTS), which takes advantage of a reduction in the protease susceptibility of the target protein upon drug binding. DARTS is universally applicable because it requires no modification of the drug and is independent of the mechanism of drug action.

Proteomics to identify proteins interacting with P2X2 ligand-gated cation channels.

Ligand-gated ion channels underlie synaptic communication in the nervous system(1). In mammals there are three families of ligand-gated channels: the cys loop, the glutamate-gated and the P2X receptor channel family(2). In each case binding of transmitter leads to the opening of a pore through which ions flow down their electrochemical gradients.

Protein phosphatase 2Cm is a critical regulator of branched-chain amino acid catabolism in mice and cultured cells.

The branched-chain amino acids (BCAA) are essential amino acids required for protein homeostasis, energy balance, and nutrient signaling. In individuals with deficiencies in BCAA, these amino acids can be preserved through inhibition of the branched-chain-alpha-ketoacid dehydrogenase (BCKD) complex, the rate-limiting step in their metabolism. BCKD is inhibited by phosphorylation of its E1alpha subunit at Ser293, which is catalyzed by BCKD kinase.

Loss of Bmx nonreceptor tyrosine kinase prevents pressure overload-induced cardiac hypertrophy.

Bmx nonreceptor tyrosine kinase has an established role in endothelial and lymphocyte signaling; however, its role in the heart is unknown. To determine whether Bmx participates in cardiac growth, we subjected mice deficient in the molecule (Bmx knockout mice) to transverse aortic constriction (TAC). In comparison with wild-type mice, which progressively developed massive hypertrophy following TAC, Bmx knockout mice were resistant to TAC-induced cardiac growth at the organ and cell level.

Cardiovascular Initiative of the Human Proteome Organisation, 5th Workshop October 2007, Seoul, Korea.

The Cardiovascular Initiative (CVI) of the Human Proteome Organisation (HUPO) held its fifth workshop prior to the Sixth Annual HUPO World Congress in Seoul, Korea in October 2007. The objectives of this report are as follows: to trace the (relatively brief) history of the CVI for those who may not be acquainted with it; to highlight lectures given by members of the CVI during this Workshop; and to make the community aware of the aims of this Initiative, including collaborative projects currently under consideration.

Proteomic and phototoxic characterization of melanolipofuscin: correlation to disease and model for its origin.

Purpose: Melanolipofuscin (MLF) is a complex granule, exhibiting properties of both melanosomes and lipofuscin (LF) granules, which accumulates in retinal pigment epithelial (RPE) cells and may contribute to the etiology of age-related macular degeneration (AMD). MLF accumulation has been reported by Feeney-Burns to more closely reflect the onset of AMD than the accumulation of lipofuscin. In an effort to assess the possible contribution MLF may have to the onset of AMD, we analyzed the phototoxicity and protein composition of MLF and compared those results to that of LF.

Examining the proteins of functional retinal lipofuscin using proteomic analysis as a guide for understanding its origin.

Purpose: To elucidate the origins of biologically active retinal lipofuscin (RLF) by examining its protein composition.

Methods: Total protein and total lipid were extracted and quantified. Proteins in this lipoprotein granule were identified by limited-scale proteomic analysis using both two-dimensional (2D) gel electrophoresis and SDS-PAGE coupled with MALDI-QqToF MSMS and automated LCMSMS, respectively.