Small molecule agonist of mitochondrial fusion repairs mitochondrial dysfunction.

Membrane dynamics are important to the integrity and function of mitochondria. Defective mitochondrial fusion underlies the pathogenesis of multiple diseases. The ability to target fusion highlights the potential to fight life-threatening conditions.

Perturbation of base excision repair sensitizes breast cancer cells to APOBEC3 deaminase-mediated mutations.

Abundant APOBEC3 (A3) deaminase-mediated mutations can dominate the mutational landscape ('mutator phenotype') of some cancers, however, the basis of this sporadic vulnerability is unknown. We show here that elevated expression of the bifunctional DNA glycosylase, NEIL2, sensitizes breast cancer cells to A3B-mediated mutations and double-strand breaks (DSBs) by perturbing canonical base excision repair (BER). NEIL2 usurps the canonical lyase, APE1, at abasic sites in a purified BER system, rendering them poor substrates for polymerase β.

Calumenin-1 Interacts with Climp63 to Cooperatively Determine the Luminal Width and Distribution of Endoplasmic Reticulum Sheets.

The ER is composed of distinct structures like tubules, matrices, and sheets, all of which are important for its various functions. However, how these distinct ER structures, especially the perinuclear ER sheets, are formed remains unclear. We report here that the ER membrane protein Climp63 and the ER luminal protein calumenin-1 (Calu1) collaboratively maintain ER sheet morphology.

BmCREC is an endoplasmic reticulum (ER) resident protein and required for ER/Golgi morphology.

Silkworm posterior silkgland is a model for studying intracellular trafficking. Here, using this model, we identify several potential cargo proteins of BmKinesin-1 and focus on one candidate, BmCREC. BmCREC (also known as Bombyx mori DNA supercoiling factor, BmSCF) was previously proposed to supercoil DNA in the nucleus.

The intracellular transport and secretion of calumenin-1/2 in living cells.

Calumenin isoforms 1 and 2 (calu-1/2), encoded by the CALU gene, belong to the CREC protein family. Calu-1/2 proteins are secreted into the extracellular space, but the secretory process and regulatory mechanism are largely unknown. Here, using a time-lapse imaging system, we visualized the intracellular transport and secretory process of calu-1/2-EGFP after their translocation into the ER lumen.

The tau-like protein in silkworm (Bombyx mori) induces microtubule bundle formation.

Tau proteins are major microtubule-associated proteins (MAPs), which promote polymerization of tubulin and determine spacings between microtubules in axons of both the central and peripheral nervous systems (CNS and PNS). Here, we cloned and identified a tau-like protein BmTau from silkworm, Bombyx mori (GenBank accession number FJ904935). The coding sequence of BmTau is 723 bases long and encodes an approximate 30 kDa protein.

Silkworm coatomers and their role in tube expansion of posterior silkgland.

Background: Coat protein complex I (COPI) vesicles, coated by seven coatomer subunits, are mainly responsible for Golgi-to-ER transport. Silkworm posterior silkgland (PSG), a highly differentiated secretory tissue, secretes fibroin for silk production, but many physiological processes in the PSG cells await further investigation.

Methodology/principal Findings: Here, to investigate the role of silkworm COPI, we cloned six silkworm COPI subunits (α, β, β', δ, ε, and ζ-COP), determined their peak expression in day 2 in fifth-instar PSG, and visualized the localization of COPI, as a coat complex, with cis-Golgi.

Characterization of kinesin-like proteins in silkworm posterior silk gland cells.

Kinesins are microtubule-based motors involved in various intracellular transports. Neurons, flagellated cells, and pigment cells have been traditionally used as model systems to study the cellular functions of kinesins. Here, we report silkworm posterior silkgland (PSG), specialized cells with an extensive endomembrane system for intracellular transport and efficient secretion of fibroin, as a novel model for kinesin study.