MAB380 Sigma-AldrichAnti-Tubulin β Antibody, clone 5H1

Here we describe the function of a previously uncharacterized protein, named family with sequence similarity 60 member A (FAM60A) that maps to chromosome 12p11 in humans. We use quantitative proteomics to determine that the main biochemical partners of FAM60A are subunits of the Sin3 deacetylase complex and show that FAM60A resides in active HDAC complexes. In addition, we conduct gene expression pathway analysis and find that FAM60A regulates expression of genes that encode components of the TGF-beta signaling pathway. Moreover, our studies reveal that loss of FAM60A or another component of the Sin3 complex, SDS3, leads to a change in cell morphology and an increase in cell migration. These studies reveal the function of a previously uncharacterized protein and implicate the Sin3 complex in suppressing cell migration.

Poly(ethylene glycol) (PEG) hydrogels are being developed as cell delivery vehicles that have great potential to improve neuronal replacement therapies. Current research priorities include (1) characterizing neural cell growth within PEG hydrogels relative to standard culture systems and (2) generating neuronal-enriched populations within the PEG hydrogel environment. This study compares the percentage of neural precursor cells (NPCs), neurons, and glia present when dissociated neural cells are seeded within PEG hydrogels relative to standard monolayer culture. Results demonstrate that PEG hydrogels enriched the initial cell population for NPCs, which subsequently gave rise to neurons, then to glia. Relative to monolayer culture, PEG hydrogels maintained an increased percentage of NPCs and a decreased percentage of glia. This neurogenic advantage of PEG hydrogels is accentuated in the presence of basic fibroblast growth factor and epidermal growth factor, which more potently increase NPC and neuronal expression markers when applied to cells cultured within PEG hydrogels. Finally, this work demonstrates that glial differentiation can be selectively eliminated upon supplementation with a γ-secretase inhibitor. Together, this study furthers our understanding of how the PEG hydrogel environment influences neural cell composition and also describes select soluble factors that are useful in generating neuronal-enriched populations within the PEG hydrogel environment.

Postsynaptic density (PSD) is a protein supramolecule lying underneath the postsynaptic membrane of excitatory synapses and has been implicated to play important roles in synaptic structure and function in mammalian central nervous system. Here, PSDs were isolated from two distinct regions of porcine brain, cerebral cortex and cerebellum. SDS-PAGE and Western blotting analyses indicated that cerebral and cerebellar PSDs consisted of a similar set of proteins with noticeable differences in the abundance of various proteins between these samples. Subsequently, protein localization in these PSDs was analyzed by using the Nano-Depth-Tagging method. This method involved the use of three synthetic reagents, as agarose beads whose surface was covalently linked with a fluorescent, photoactivable, and cleavable chemical crosslinker by spacers of varied lengths. After its application was verified by using a synthetic complex consisting of four layers of different proteins, the Nano-Depth-Tagging method was used here to yield information concerning the depth distribution of various proteins in the PSD. The results indicated that in both cerebral and cerebellar PSDs, glutamate receptors, actin, and actin binding proteins resided in the peripheral regions within ∼ 10 nm deep from the surface and that scaffold proteins, tubulin subunits, microtubule-binding proteins, and membrane cytoskeleton proteins found in mammalian erythrocytes resided in the interiors deeper than 10 nm from the surface in the PSD. Finally, by using the immunoabsorption method, binding partner proteins of two proteins residing in the interiors, PSD-95 and α-tubulin, and those of two proteins residing in the peripheral regions, elongation factor-1α and calcium, calmodulin-dependent protein kinase II α subunit, of cerebral and cerebellar PSDs were identified. Overall, the results indicate a striking similarity in protein organization between the PSDs isolated from porcine cerebral cortex and cerebellum. A model of the molecular structure of the PSD has also been proposed here.

Olanzapine (OLZ) is an atypical antipsychotic whose clinical efficacy is hampered by side effects including weight gain and diabetes. Recent evidence shows that OLZ alters insulin sensitivity independent of changes in body weight and composition. The present study addresses whether OLZ-induced insulin resistance is driven by its central actions.Sprague-Dawley rats received an intravenous (OLZ-IV group) or intracerebroventricular (OLZ-ICV group) infusion of OLZ or vehicle. Glucose kinetics were assessed before (basal period) and during euglycemic-hyperinsulinemic clamp studies.OLZ-IV caused a transient increase in glycemia and a higher rate of glucose appearance (R(a)) in the basal period. During the hyperinsulinemic clamp, the glucose infusion rate (GIR) required to maintain euglycemia and the rate of glucose utilization (R(d)) were decreased in OLZ-IV, whereas endogenous glucose production (EGP) rate was increased compared with vehicle-IV. Consistent with an elevation in EGP, the OLZ-IV group had higher hepatic mRNA levels for the enzymes glucose-6-phosphatase and phosphoenolpyruvate carboxykinase. Phosphorylation of hypothalamic AMP-activated protein kinase (AMPK) was increased in OLZ-IV rats compared with controls. Similarly, an intracerebroventricular infusion of OLZ resulted in a transient increase in glycemia as well as a higher R(a) in the basal period. During the hyperinsulinemic period, OLZ-ICV caused a decreased GIR, an increased EGP, but no change in R(d). Furthermore, OLZ-ICV rats had increased hepatic gluconeogenic enzymes and elevated hypothalamic neuropeptide-Y and agouti-related protein mRNA levels.Acute central nervous system exposure to OLZ induces hypothalamic AMPK and hepatic insulin resistance, pointing to a hypothalamic site of action for the metabolic dysregulation of atypical antipsychotics.

Among the proinflammatory mediators, platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine) is a major primary and secondary messenger involved in intracellular and extracellular communication. Evidence suggests that PAF plays a significant role in oncogenic transformation, tumor growth, angiogenesis, and metastasis. However, PAF, with its receptor (PAFR) and their downstream signaling targets, has not been thoroughly studied in cancer. Here, we characterized the PAFR expression pattern in 4 normal human ovarian surface epithelial (HOSE) cell lines, 13 ovarian cancer cell lines, paraffin blocks (n = 84), and tissue microarrays (n = 230) from patients with ovarian cancer. Overexpression of PAFR was found in most nonmucinous types of ovarian cancer but not in HOSE and mucinous cancer cells. Correspondingly, PAF significantly induced cell proliferation and invasion only in PAFR-positive cells (i.e., OVCA429 and OVCA432), but not in PAFR-negative ovarian cells (HOSE and mucinous RMUG-L). The dependency of cell proliferation and invasion on PAFR was further confirmed using PAFR-specific small interfering RNA gene silencing probes, antibodies against PAFR and PAFR antagonist, ginkgolide B. Using quantitative multiplex phospho-antibody array technology, we found that tyrosine phosphorylation of EGFR/Src/FAK/paxillin was coordinately activated by PAF treatment, which was correlated with the activation of phosphatidylinositol 3-kinase and cyclin D1 as markers for cell proliferation, as well as matrix metalloproteinase 2 and 9 for invasion. Specific tyrosine Src inhibitor (PP2) reversibly blocked PAF-activated cancer cell proliferation and invasion. We suggest that PAFR is an essential upstream target of Src and other signal pathways to control the PAF-mediated cancer progression.

A growing body of evidence supports the notion that soluble oligomeric forms of the amyloid beta-peptide (Abeta) may be the proximate effectors of neuronal injuries and death in the early stages of Alzheimer disease. However, the molecular mechanisms associated with neuronal apoptosis induced by soluble Abeta remain to be elucidated. We recently demonstrated the involvement of an early reactive oxygen species-dependent perturbation of the microtubule network (Sponne, I., Fifre, A., Drouet, B., Klein, C., Koziel, V., Pincon-Raymond, M., Olivier, J.-L., Chambaz, J., and Pillot, T. (2003) J. Biol. Chem. 278, 3437-3445). Because microtubule-associated proteins (MAPs) are responsible for the polymerization, stabilization, and dynamics of the microtubule network, we investigated whether MAPs might represent the intracellular targets that would enable us to explain the microtubule perturbation involved in soluble Abeta-mediated neuronal apoptosis. The data presented here show that soluble Abeta oligomers induce a time-dependent degradation of MAP1A, MAP1B, and MAP2 involving a perturbation of Ca2+ homeostasis with subsequent calpain activation that, on its own, is sufficient to induce the proteolysis of isoforms MAP2a, MAP2b, and MAP2c. In contrast, MAP1A and MAP1B sequential proteolysis results from the Abeta-mediated activation of caspase-3 and calpain. The prevention of MAP1A, MAP1B, and MAP2 proteolysis by antioxidants highlights the early reactive oxygen species generation in the perturbation of the microtubule network induced by soluble Abeta. These data clearly demonstrate the impact of cytoskeletal perturbations on soluble Abeta-mediated cell death and support the notion of microtubule-stabilizing agents as effective Alzheimer disease drugs.

Platelet-activating factor (PAF), a phospholipid second messenger, has diverse physiological functions, including responses in differentiated endothelial cells to external stimuli. We used human umbilical vein endothelial cells (HUVECs) as a model system. We show that PAF activated pertussis toxin-insensitive G alpha(q) protein upon binding to its seven transmembrane receptor. Elevated cAMP levels were observed via activation of adenylate cyclase, which activated protein kinase A (PKA) and was attenuated by a PAF receptor antagonist, blocking downstream activity. Phosphorylation of Src by PAF required G alpha(q) protein and adenylate cyclase activation; there was an absolute requirement of PKA for PAF-induced Src phosphorylation. Immediate (1 min) PAF-induced STAT-3 phosphorylation required the activation of G alpha(q) protein, adenylate cyclase, and PKA, and was independent of these intermediates at delayed (30 min) and prolonged (60 min) PAF exposure. PAF activated PLC beta 3 through its G alpha(q) protein-coupled receptor, whereas activation of phospholipase C gamma 1 (PLC gamma 1) by PAF was independent of G proteins but required the involvement of Src at prolonged PAF exposure (60 min). We demonstrate for the first time in vascular endothelial cells: (i) the involvement of signaling intermediates in the PAF-PAF receptor system in the induction of TIMP2 and MT1-MMP expression, resulting in the coordinated proteolytic activation of MMP2, and (ii) a receptor-mediated signal transduction cascade for the tyrosine phosphorylation of FAK by PAF. PAF exposure induced binding of p130(Cas), Src, SHC, and paxillin to FAK. Clearly, PAF-mediated signaling in differentiated endothelial cells is critical to endothelial cell functions, including cell migration and proteolytic activation of MMP2.