13 research outputs found
Laminin-based cell adhesion anchors microtubule plus ends to the epithelial cell basal cortex through LL5Ī±/Ī²
A newly discovered interaction between LL5s, laminins, and integrins reveals how the extracellular matrix directs microtubule polarity in epithelial tissues
Synaptic activity prompts Ī³-secretaseāmediated cleavage of EphA4 and dendritic spine formation
Alzheimer's disease is an age-dependent neurodegenerative disorder that is characterized by a progressive decline in cognitive function. Ī³-secretase dysfunction is evident in many cases of early onset familial Alzheimer's disease. However, the mechanism by which Ī³-secretase dysfunction results in memory loss and neurodegeneration is not fully understood. Here, we demonstrate that Ī³-secretase is localized at synapses and regulates spine formation. We identify EphA4, one of the Ephrin receptor family members, as a substrate of Ī³-secretase, and find that EphA4 processing is enhanced by synaptic activity. Moreover, overexpression of EphA4 intracellular domain increases the number of dendritic spines by activating the Rac signaling pathway. These findings reveal a function for EphA4-mediated intracellular signaling in the morphogenesis of dendritic spines and suggest that the processing of EphA4 by Ī³-secretase affects the pathogenesis of Alzheimer's disease
Retrieval of temperature profiles using radio acoustic sounding system (RASS) with the equatorial atmosphere radar (EAR) in West Sumatra, Indonesia
Abstract The radio acoustic sounding system (RASS) with the equatorial atmosphere radar (EAR) at Koto Tabang, Indonesia was adapted to test the effects of the acoustic source location and acoustic frequency range on the continuous measurement of height profiles of temperature in the tropical troposphere. We installed the acoustic transmitting system by using six high-power horn speakers and four subwoofers. We developed a three-dimensional ray-tracing method of acoustic waves to predict the shape of acoustic wavefronts, accounting for the effects of the background winds on acoustic wave propagation. Then, we selected the appropriate antenna beam directions for EAR that satisfy the Bragg condition between the radar and acoustic wave propagation vectors. We carried out eight campaign observations in 2016, testing the performance of EARāRASS. We found that the location and acoustic frequency range affected the RASS echoes. We also tested the compensation method of the background wind velocity with EAR to obtain the true sound speed. We intensively analyzed the RASS results from August 29 to September 3, 2016, when radiosondes were launched 12 times from the EAR site. We successfully retrieved the temperature profiles from RASS from 2 to 6ā14Ā km with time and height resolutions of about 10Ā min and 150Ā m, respectively. Some temperature profiles were obtained up to about the tropopause at 17Ā km, although the observation period was short. During the RASS campaign, we detected a few interesting events regarding temperature variations as well as large perturbations in the three components of wind velocity