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Results reveal that the reductive cleavage of anisylidene acetals by BH3/Bu2BOTf can selectively produce either regioisomer, simply by adjusting the reaction temperatures and reagent concentrations. Reductive ring opening at low temperatures is determined to be compatible with sensitive functional groups such as allyl and enol ethers and other ketals.

Sulfated epitopes of [alpha]-glucosamine (GlcN sulfoforms) are prepared by using solid-phase synthesis as models of internal glucosamines within heparan sulfate. The fragmentation analysis has distinguished GlcN sulfoforms bearing the relatively rare 3-O-sulfate from isomers with the more common 6-O-sulfate.

The binding of the adaptor protein APPL1 to adiponectin receptors is necessary for adiponectin-induced AMP-activated protein kinase (AMPK) activation in muscle, yet the underlying molecular mechanism remains unknown. Here we show that in muscle cells adiponectin and metformin induce AMPK activation by promoting APPL 1-dependent LKB1 cytosolic translocation. APPL1 mediates adiponectin signaling by directly interacting with adiponectin receptors and enhances LKB1 cytosolic localization by anchoring this kinase in the cytosol. Adiponectin also activates another AMPK upstream kinase Ca2+/calmodulin-dependent protein kinase kinase by activating phospholipase C and subsequently inducing Ca2+ release from the endoplasmic reticulum, which plays a minor role in AMPK activation. Our results show that in muscle cells adiponectin is able to activate AMPK via two distinct mechanisms as follows: a major pathway (the APPL1/LKB1dependent pathway) that promotes the cytosolic localization of LKB1 and a minor pathway (the phospholipase C/Ca2+/Ca2+/calmodulin-dependent protein kinase kinase-dependent pathway) that stimulates Ca2+ release from intracellular stores. [ABSTRACT FROM AUTHOR]