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Full-Text Articles in Life Sciences

Cortactin Regulates Cell Migration Via Activation Of N-Wasp, Jennifer Kowalski, C. Egile, S. Gil, S. Snapper, R. Li, S. Thomas Sep 2010

Cortactin Regulates Cell Migration Via Activation Of N-Wasp, Jennifer Kowalski, C. Egile, S. Gil, S. Snapper, R. Li, S. Thomas

Jennifer Kowalski

Cortactin is an actin-associated scaffolding protein that regulates cell migration. Amplification of the human gene, EMS1, has been detected in breast, head and neck tumors, where it correlates with increased invasiveness. Cortactin can regulate actin dynamics directly via its N-terminal half, which can bind and activate the Arp2/3 complex. The C-terminal portion of cortactin, however, is thought to have limited function in its regulation of the actin polymerization machinery. In this report, we identify a role for the cortactin C-terminus in regulating cell migration and, more specifically, actin dynamics. Overexpression of either full-length cortactin or cortactin C-terminus is sufficient to …


Münch, Morphology, Microfluidics – Our Structural Problem With The Phloem [Review Article], Michael Knoblauch, Winfried S. Peters Aug 2010

Münch, Morphology, Microfluidics – Our Structural Problem With The Phloem [Review Article], Michael Knoblauch, Winfried S. Peters

Winfried S. Peters

The sieve tubes of the phloem are enigmatic structures. Their role as channels for the distribution of assimilates was established in the 19th century, but their sensitivity to disturbations has hampered the elucidation of their transport mechanisms and its regulation ever since. Ernst Münch's classical monograph of 1930 is generally regarded as the first coherent theory of phloem transport, but the ‘Münchian’ pressure flow mechanism had been discussed already before the turn of the century. Münch's impact rather rested on his simple physical models of the phloem that visualized pressure flow in an intuitive way, and we argue that the …


Microfluidics-Integrated Time-Lapse Imaging For Analysis Of Cellular Dynamics, Dirk Albrecht, Gregory Underhill, Joshua Resnikoff, Avital Mendelson, Sangeeta Bhatia, Jagesh Shah May 2010

Microfluidics-Integrated Time-Lapse Imaging For Analysis Of Cellular Dynamics, Dirk Albrecht, Gregory Underhill, Joshua Resnikoff, Avital Mendelson, Sangeeta Bhatia, Jagesh Shah

Dirk R. Albrecht

An understanding of the mechanisms regulating cellular responses has recently been augmented by innovations enabling the observation of phenotypes at high spatio-temporal resolution. Technologies such as microfluidics have sought to expand the throughput of these methods, although assimilation with advanced imaging strategies has been limited. Here, we describe the pairing of high resolution time-lapse imaging with microfluidic multiplexing for the analysis of cellular dynamics, utilizing a design selected for facile fabrication and operation, and integration with microscopy instrumentation. This modular, medium-throughput platform enables the long-term imaging of living cells at high numerical aperture (via oil immersion) by using a conserved …


Legume Phylogeny And The Evolution Of A Unique Contractile Apparatus That Regulates Phloem Transport, Winfried Peters, Claudia Hanakam, Dietmar Haffer, Aart Van Bel, Michael Knoblauch Mar 2010

Legume Phylogeny And The Evolution Of A Unique Contractile Apparatus That Regulates Phloem Transport, Winfried Peters, Claudia Hanakam, Dietmar Haffer, Aart Van Bel, Michael Knoblauch

Winfried S. Peters

Protein bodies called forisomes undergo Ca2+-dependent deformations to occlude sieve tubes reversibly, providing a unique regulatory mechanism of phloem transport. Because forisomes are known exclusively from the Papilionoideae (Leguminosae), the evolution of forisome function may have played a role in the rapid radiation of this huge taxon. The unexpected discovery of a papilionoid species lacking forisomes led us to evaluate a representative set of species covering 33 of the 36 legume tribes traditionally recognized. We found forisomes in Papilionoideae but not in Caesalpinioideae and Mimosoideae. Forisomes were absent from several species of the papilionoid tribe Galegeae. Forisomes with tail-like protrusions …