Cysteine string protein 1 (CSP1) modulates insulin sensitivity by attenuating glucose transporter 4 (GLUT4) vesicle docking with the plasma membrane

Insulin stimulates glucose transporter 4 (GLUT4) vesicle recruitment from its intracellular storage site to the plasma membrane. Cysteine string protein 1 (CSP1) is a SNARE-binding protein involved in the vesicular trafficking of neurotransmitters and other exocytic processes. In this study, we investigated the involvement of CSP1 in insulin-dependent GLUT4 recruitment in 3T3-L1 adipocytes. Over-expression of wild-type CSP1 led to attenuated insulin-stimulated glucose uptake without any change in GLUT4 content in the plasma membrane, rather it inhibits docking by blocking the association of VAMP2 with syntaxin 4. In contrast, knockdown of CSP1 enhanced insulin-stimulated glucose uptake. The mRNA and protein expression of CSP1 was elevated in 3T3-L1 adipocytes in insulin resistant states caused by high levels of palmitate and chronic insulin exposure. Taken together, the results of this study suggest that CSP1 is involved in insulin resistance by interrupting GLUT4 vesicle docking with the plasma membrane

Climatic jump in the polar region (II): Preliminary study of sea surface temperature

By using the COADS (Comprehensive Ocean-Atmosphere Data Set) data, we have examined sea-surface temperature (SST). Although the region of analyses is limited, we may give the following conclusion : the SST in the mid latitudes of the Pacific and Atlantic Ocean abruptly increased around 1940; and they are rather larger than those in the other area, i. e. the high latitudes and eastern Atlantic Ocean, even though the SST in the central and eastern Pacific Ocean is deduced from the other investigators\u27 results. Taking account of ROLL\u27s result and our estimate of the random error, we may infer that the increase of SST is real, in spite of contamination of the effect due to the change of observing method, i. e. the "bucket method" or the "intake method"

The dietary effect of milk sphingomyelin on the lipid metabolism of obese/diabetic KK-A(y) mice and wild-type C57BL/6J mice

Purified milk sphingomyelin (SM) was obtained from lipid concentrated butter serum (LC-BS) by successive separations involving solvent fractionation, selective saponification, and silicic acid column chromatography. The SM obtained was given to obese/diabetic KK-A(y) mice and wild-type C57BL/6J mice. SM supplementation significantly increased fecal lipids paralleled with a decrease in non-HDL cholesterol levels in the serum and neutral lipids and in cholesterol levels in the livers of KK-A(y) mice. The reduction of liver lipid levels also resulted in a decrease in the total fatty acid content of the KK-A(y) mice livers, while n-3 fatty acids derived from the conversion of a-linolenic acid (18:3n-3) increased due to SM supplementation. In contrast to the KK-A(y) mice, little change in the serum and liver lipids was observed in wild-type C57BL/6J mice. The present study suggests that SM may be effective only in subjects with metabolic disorders