Apolipoprotein E and peptide mimetics modulate inflammation by binding the SET protein and activating protein phosphatase 2A

The molecular mechanism by which apolipoprotein E (apoE) suppresses inflammatory cytokine and NO production is unknown. Using an affinity purification approach, we found that peptide mimetics of apoE, derived from its receptor binding domain residues 130-150, bound to the SET protein, which is a potent physiological inhibitor of protein phosphatase 2A (PP2A). Both holo-apoE protein and apoE-mimetic peptides bound to the C-terminal region of SET, which is then associated with an increase in PP2A-mediated phosphatase activity. As physiological substrates for PP2A, the LPS-induced phosphorylation status of signaling MAPK and Akt kinase is reduced following treatment with apoE-mimetic peptides. On the basis of our previous report, in which apoE-mimetic peptides reduced I-κB kinase and NF-κB activation, we also demonstrate a mechanism for reduced production of inducible NO synthase protein and its NO product. These data provide evidence for a novel molecular mechanism by which apoE and apoE-mimetic peptides antagonize SET, thereby enhancing endogenous PP2A phosphatase activity, which reduces levels of phosphorylated kinases, signaling, and inflammatory response.     

Preferential binding of a kinesin-1 motor to GTP-tubulin�Crich microtubules underlies polarized vesicle transport

Polarized transport in neurons is fundamental for the formation of neuronal circuitry. A motor domain–containing truncated KIF5 (a kinesin-1) recognizes axonal microtubules, which are enriched in EB1 binding sites, and selectively accumulates at the tips of axons. However, it remains unknown what cue KIF5 recognizes to result in this selective accumulation. We found that axonal microtubules were preferentially stained by the anti–GTP-tubulin antibody hMB11. Super-resolution microscopy combined with EM immunocytochemistry revealed that hMB11 was localized at KIF5 attachment sites. In addition, EB1, which binds preferentially to guanylyl-methylene-diphosphate (GMPCPP) microtubules in vitro, recognized hMB11 binding sites on axonal microtubules. Further, expression of hMB11 antibody in neurons disrupted the selective accumulation of truncated KIF5 in the axon tips. In vitro studies revealed approximately threefold stronger binding of KIF5 motor head to GMPCPP microtubules than to GDP microtubules. Collectively, these data suggest that the abundance of GTP-tubulin in axonal microtubules may underlie selective KIF5 localization and polarized axonal vesicular transport.     

Photoprotective function of betacyanin in leaves of <Emphasis Type="Italic">Amaranthus cruentus</Emphasis> L. under water stress

The photoprotective function of leaf betacyanin in water-stressed Amaranthus cruentus plants was examined by comparing leaves of two strains which differ significantly in the amount of betacyanin. At 0, 1, and 2 days after the imposed water stress, leaves were subjected to high-light (HL) treatment to assess their photosynthetic capacity and photoinhibition susceptibility. The water stress equally reduced leaf relative water content (RWC), gas-exchange rate and chlorophyll (Chl) contents in both leaves, indicating that the severity of water stress was comparable between the strains. Consequently, the extent of photoinhibition after the HL treatment increased in both strains as water stress developed; however, it was significantly greater in acyanic leaves than in betacyanic leaves, suggesting lower photoinhibition susceptibility in the betacyanic strain. The betacyanic leaves also exhibited approximately 30% higher values for photochemical quenching coefficient (q_P) during the period of water stress despite the nonphotochemical quenching coefficient (q_N) did not differ significantly between the strains. These results may be partially explained by the increased amount of leaf betacyanin under water stress. Moreover, a decrease in Chl content in betacyanic leaves might have enhanced light screening effect of betacyanin by increasing relative abundance of betacyanin to Chl molecule. In addition, reduced Chl content increased light penetrability of leaves. As a result, the extent of photoinhibition at the deeper tissue was exacerbated and the Chl fluorescence emitted from these tissues was more readily detected, facilitating assessment of photoinhibition at deeper tissues where the effect of betacyanic light screening is considered to be most apparent. Our results demonstrated that leaf betacyanin contributes to total photoprotective capacity of A. cruentus leaves by lowering excitation pressure on photosystem II (PSII) via attenuation of potentially harmful excess incident light under water stress.     

Chemical biology of abscisic acid

Chemical biology is a discipline that utilizes chemicals to elucidate biological mechanisms and physiological functions. Various abscisic acid (ABA) derivatives have revealed the structural requirement for the perception by ABA receptors while biotin or caged derivatives of ABA have disclosed the localization of several ABA-binding proteins. Recently, selective ABA agonist has been used to identify ABA receptors. Furthermore, ABA biosynthesis and catabolic inhibitors have contributed to the identification of new ABA functions in plant growth and development. The physiological function of ABA in non-plant organisms has gradually been revealed. In this review, we discuss the development of small bioactive chemicals and their significance in ABA research.     

Visualization of gluten and starch distributions in dough by fluorescence fingerprint imaging

A novel method combining imaging techniques and fluorescence fingerprint (FF) data measurement was developed to visualize the distributions of gluten and starch in dough without any preprocessing. Fluorescence images of thin sections of gluten, starch, and dough were acquired under 63 different combinations of excitation and emission wavelengths, resulting in a set of data consisting of the FF data for each pixel. Cosine similarity values between the FF of each pixel in the dough and those of gluten and starch were calculated. Each pixel was colored according to the cosine similarity value to obtain a pseudo-color image showing the distributions of gluten and starch. The dough sample was then fluorescently stained for gluten and starch. The stained image showed patterns similar to the pseudo-color FF image, validating the effectiveness of the FF imaging method. The method proved to be a powerful visualization tool, applicable in fields other than food technology.     

A Molecular Motor,KIF13A,Controls Anxiety by Transporting the Serotonin Type 1A Receptor

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Highlights? Kif13a^?/? mice show elevated-anxiety-like behavioral defects ? 5HT_1A receptors are not properly transported in Kif13a^?/? neurons ? The forkhead-associated domain of KIF13A associates directly with 5HT_1A receptors ? KIF13A can translocate 5HT_1A receptors in vivo and in vitro