Interplay between N-WASP and CK2 optimizes clathrin-mediated endocytosis of EGFR.

Clathrin-mediated endocytosis (CME) involves spatially and temporally restricted molecular dynamics, to which protein kinases and actin contribute. However, whether and how these two elements merge to properly execute CME remains unknown. Here, we show that neural Wiskott-Aldrich syndrome protein (N-WASP) and casein kinase 2 (CK2) form a complex and localize to clathrin-coated vesicles.

Human USP3 is a chromatin modifier required for S phase progression and genome stability.

Protein ubiquitination is critical for numerous cellular functions, including DNA damage response pathways. Histones are the most abundant monoubiquitin conjugates in mammalian cells; however, the regulation and the function of monoubiquitinated H2A (uH2A) and H2B (uH2B) remain poorly understood. In particular, little is known about mammalian deubiquitinating enzymes (DUBs) that catalyze the removal of ubiquitin from uH2A/uH2B.

A new approach for the detection and identification of protein impurities using combinatorial solid phase ligand libraries.

We propose a novel method for detection of protein impurities present in plasma-derived and recombinant purified injectable biopharmaceuticals by enhancing the concentration of protein impurities, in essence "amplifying" their presence to detectable levels. The method is based on the capture of proteins using a combinatorial solid-phase hexapeptides ligand library previously described for the reduction of protein concentration difference in biological fluids. Three proteins have been investigated: Staphylococcus aureus Protein A, expressed in Escherichia coli and supplied as 99% pure, recombinant human albumin, expressed in Pichia pastoris and certified as 95% pure, and therapeutic albumin supplied as 96-98% pure injectable solution.

Proteomic analysis of pancreatic ductal carcinoma cells after combined treatment with gemcitabine and trichostatin A.

The human pancreatic adenocarcinoma cell line T3M4 has been treated with two agents, gemcitabine (2',2'-difluorodeoxycytidine, a drug interfering with DNA synthesis) and trichostatin A (a drug interfering with histone acetylation), both separately and in association. The association of the two drugs showed a marked cooperative effect in inhibiting proliferation and inducing apoptosis of the cells. In an effort to identify differentially expressed proteins in the different drug treatments, the proteomic expression has been studied by two-dimensional gel electrophoresis comparing untreated cells with cells treated with trichostatin A and/or gemcitabine.

Spot overlapping in two-dimensional maps: a serious problem ignored for much too long.

In the analysis of a neuroblastoma xenograft implanted in mice using two-dimensional maps, some 85 proteins were found to be up- or down-regulated (out of a total of 264 detected by a medium-sensitivity colloidal Coomassie stain). When these spots were eluted and analysed by mass spectrometry in a quadrupole time of flight mass spectrometer, a number of spots were found to be envelopes of different polypeptide chains. Out of a total of 74 proteins identified, 52 (71%) were found to be singlets, 14 (19%) were doublets, 6 (8%) were triplets, 1 was a quadruplet and 1 a quintuplet.