biosights: March 17, 2014 - Blebs lead the way in Dictyostelium chemotaxis

submitted by: JCB
Membrane blebs can help the leading edge of migrating cells protrude forwards, but the contribution of blebs to the motility of Dictyostelium cells is unclear. Zatulovskiy et al. reveal that blebs form at the front of chemotaxing Dictyostelium cells, particularly when the cells are faced with a mechanically resistant environment, and that this process is guided by a PI3-kinase-dependent signaling pathway. This biosights episode presents the paper by Zatulovskiy et al. from the March 17,...

biosights: February 17, 2014 - Shroom takes embryos to new dimensions

submitted by: JCB
During development, the planar polarized distribution of Rho kinase and Myosin II helps Drosophila germ-band cells intercalate so that the embryo extends along its anterior-posterior axis. Simoes et al. reveal how Rho GTPase and the actin-binding protein Shroom combine to regulate the localization of Rho kinase and actomyosin contractility during axis elongation. This biosights episode presents the paper by Simoes et al. from the February 17, 2014, issue of The Journal of Cell Biology and...

Melanin-concentrating hormone receptor 1 polymorphisms are associated with components of energy balance in the CODING study

submitted by: bfontain
BACKGROUND: The melanin-concentrating hormone receptor 1 (MCHR1) is a G protein-coupled receptor that regulates energy balance and body composition in animal models. Inconsistent effects of MCHR1 polymorphisms on energy homeostasis in humans may partly be attributable to environmental factors. OBJECTIVES: We examined the effect of 4 single nucleotide polymorphisms (rs133073, rs133074, rs9611386, and rs882111) in the MCHR1 gene on body composition as well as energy-related lifestyle...
Authors: Bénédicte Fontaine-Bisson, James Thorburn, Anne Gregory, Hongwei Zhang, Guang Sun

biosights: January 20, 2014 - Motors give a new twist to platelet activation

submitted by: JCB
The discoid shape of resting platelets is maintained by a peripheral ring of bundled microtubules called the marginal band. Diagouraga et al. reveal that, upon platelet activation, the motor protein dynein slides microtubules apart, inducing marginal band coiling and the conversion of platelets to a spherical shape. This biosights episode presents the paper by Diagouraga et al. from the January 20, 2014, issue of The Journal of Cell Biology and includes an interview with senior author Karin...

Silencing the Menkes Copper-Transporting ATPase (Atp7a) Gene in Rat Intestinal Epithelial (IEC-6) Cells Increases Iron Flux via Transcriptional Induction of Ferroportin 1 (Fpn1)

submitted by: jfcollins
The Menkes copper-transporting ATPase (Atp7a) gene is induced in rat duodenum during iron deficiency, consistent with copper accumulation in the intestinal mucosa and liver. To test the hypothesis that ATP7A influences intestinal iron metabolism, the Atp7a gene was silenced in rat intestinal epithelial (IEC-6) cells using short hairpin RNA (shRNA) technology. Perturbations in intracellular copper homeostasis were noted in knockdown cells, consistent with the dual roles of ATP7A in pumping...
Authors: Sukru Gulec, James F. Collins

biosights: Decemeber 23, 2013 - Tumor cells WASH away the extracellular matrix

submitted by: JCB
Tumor cells invade through extracellular matrices by forming actin-rich structures called invadopodia, which contain the transmembrane matrix metalloproteinase MT1-MMP. Monteiro et al. reveal that the Arp2/3 activating protein WASH works with the exocyst complex to deliver MT1-MMP from late endosomes to the invadopodial plasma membrane. This biosights episode presents the paper by Monteiro et al. from the December 23, 2013, issue of The Journal of Cell Biology and includes an interview with...