Dysfunction of lipid storage droplet-2 suppresses endoreplication and induces JNK pathway-mediated apoptotic cell death in Drosophila salivary glands.

The lipid storage droplet-2 (LSD-2) protein of Drosophila is a homolog of mammalian perilipin 2, which is essential for promoting lipid accumulation and lipid droplet formation. The function of LSD-2 as a regulator of lipolysis has also been demonstrated. However, other LSD-2 functions remain unclear. To investigate the role of LSD-2, we performed tissue-specific depletion in the salivary glands of Drosophila using a combination of the Gal4-upstream activating sequence system and RNA interference. LSD-2 depletion inhibited the entry of salivary gland cells into the endoreplication cycle and delayed this process by enhancing CycE expression, disrupting the development of this organ. The deficiency of LSD-2 expression enhanced reactive oxygen species production in the salivary gland and promoted JNK-dependent apoptosis by suppressing dMyc expression. This phenomenon did not result from lipolysis. Therefore, LSD-2 is vital for endoreplication cell cycle and cell death programs.

Ir-Catalyzed substitution of propargylic-type esters with enoxysilanes.

Propargylic-type acetates react readily with enoxysilanes in the presence of 1 mol % of [Ir(cod){P(OPh)3}2]OTf activated preliminarily with molecular H2 to give beta-alkynyl ketones in high to excellent yields. Substitution at the propargyl carbon proceeds exclusively or selectively in most types of propargylic esters. Alternatively, the formation of the allenyl products is predominant in the reaction of esters, which have two phenyl groups on the propargyl carbon.