New microfluidic chip targeting phosphoproteomes

Comunicaciones a congreso

HPLC-FosfoChip una nueva tecnología para el análisis selectivo de fosfopéptidos mediante LC/MS

Comunicaciones a congreso

Regulation of cell migration and survival by focal adhesion targeting of Lasp-1

Large-scale proteomic and functional analysis of isolated pseudopodia revealed the Lim, actin, and SH3 domain protein (Lasp-1) as a novel protein necessary for cell migration, but not adhesion to, the extracellular matrix (ECM). Lasp-1 is a ubiquitously expressed actin-binding protein with a unique domain configuration containing SH3 and LIM domains, and is overexpressed in 8–12% of human breast cancers. We find that stimulation of nonmotile and quiescent cells with growth factors or ECM proteins facilitates Lasp-1 relocalization from the cell periphery to the leading edge of the pseudopodium, where it associates with nascent focal complexes and areas of actin polymerization. Interestingly, although Lasp-1 dynamics in migratory cells occur independently of c-Abl kinase activity and tyrosine phosphorylation, c-Abl activation by apoptotic agents specifically promotes phosphorylation of Lasp-1 at tyrosine 171, which is associated with the loss of Lasp-1 localization to focal adhesions and induction of cell death. Thus, Lasp-1 is a dynamic focal adhesion protein necessary for cell migration and survival in response to growth factors and ECM proteins

Mechanistic studies of the inactivation of low molecular weight protein tyrosine phosphatases

This thesis examines various inhibitors of the low molecular weight protein tyrosine phosphatases (PTPases). Phenylarsine oxide (PAO) is a widely used PTPase-specific inhibitor. PAO is known for its interaction of vicinal dithiols in proteins. However, only the low Mr PTPases possess vicinal dithiols at the enzyme active site. The results of this study suggest that PAO inhibits various classes of PTPases via different mechanisms. Naphthoquinone derivatives (NQs) have been previously studied for their potential roles as anti-cancer therapeutic agents. It has been speculated that one possible reaction in the cell might be a NQ-induced inhibition and inactivation of protein tyrosine phosphatases (PTPases) by reaction with an active site cysteine residue. The present study demonstrates the inactivation of several low molecular weight protein tyrosine phosphatases by naphthoquinone (NQ) derivatives and examines the detailed mechanism of the process. The inactivation of low Mr PTPases by 1,2-naphthoquinone (1,2NQ) derivatives was found to proceed through at least two steps: a fast equilibrium binding at the enzyme active site, with 1,2NQ acting as a competitive inhibitor, followed by a slower covalent arylation of active site cysteine(s). When 1,2NQ acted as a competitive inhibitor of a human low molecular weight PTPase isoenzyme (HPTPA), the Ki was found to be 7 μM at pH 7.0. It was also determined that in the presence of air, NQ could participate in redox reactions leading to the formation of reactive oxygen species and the subsequent oxidization of the two active site cysteines (unique to low molecular weight PTPases), which in turn led to the formation of a disulfide bond and a resulting inactivation of the enzyme. Simple thiols, such as glutathione at cellular concentrations, did not significantly retard the reaction of NQs with PTPases. Based on these results, it is likely that NQ derivatives can both directly and indirectly inactivate PTPases in the cell

opmac: one-key poly1305 mac

Chinese Acad Sci, State Key Lab Informat Secur, Inst Software, Chinese Acad Sci, CAS, Grad Univ, Natl Nat Sci Fdn ChinaIn this paper, we present One-Key Poly1305 MAC(OPMAC) and prove its security for arbitrary length message. OPMAC is deterministic and takes only one 16-byte key. Previously, Poly1305 MAC is nonce-based and requires two 16-byte keys and a 16-b

an improved poly1305 mac

Inst Infocomm ResIn this paper, we propose an improved Poly1305 MAC, called IPMAC. IPMAC is a refinement of Poly1305 MAC shown by Bernstein. We use only one 16-byte key and one 16-byte nonce for IPMAC while Poly1305 MAC uses two 16-byte keys and one 16-byte n

an efficient one-key carter-wegman message authentication code

In this paper, we present an efficient One-Key Carter-Wegman Message Authentication Code, called One-key Galois Message Authentication Code(OGMAC), and prove its security for arbitrary length message. Generally, Carter-Wegman MACs use a universal hash an

Enhanced catalytic performance of molybdenum-doped mesoporous SBA-15 for metathesis of 1-butene and ethene to propene

Molybdenum-doped mesoporous SBA-15, mesoporous SBA-15-supported MoO3/SBA-15, and traditional silica-supported MoO3/SiO2 were successfully synthesized. Various techniques, such as XRD, TEM, BET, UV-DRS, Raman, XPS and IR, were used to characterize the above obtained materials. The studies of TEM, XRD and BET confirmed that the highly ordered mesoporous structure of SBA-15 was maintained in the doped Mo-SBA-15 whereas supported MoO3/SBA-15 showed a significant reduction in surface area due to the deposition of MoO3 nanoparticles into the SBA-15 channels. XPS studies revealed that a high concentration of Mo5+ species appeared in doped Mo-SBA-15 whereas supported MoO3/SBA-15 and MoO3/SiO2 only contained Mo6+ species. The metathesis reaction of 1-butene and ethene to propene was used to evaluate the catalytic performance of Mo-containing materials. The doped Mo-SBA-15 illustrated a superior catalytic performance over the supported MoO3/SBA-15 and MoO3/SiO2 catalysts. The enhancement of catalytic performance for doped Mo-SBA-15 was assigned to the incorporation of Mo species into the SBA-15 framework. Due to the doping method, Mo-SBA-15 exhibited a well-ordered mesoporous structure, a high surface area, and a high concentration of Mo5+ species, which is beneficial to the catalytic performance for metathesis reactions