609 research outputs found
Drebrin is a novel connexin-43 binding partner that links gap junctions to the submembrane cytoskeleton
AbstractBackground: Connexins form gap junctions that mediate the transfer of ions, metabolites, and second messengers between contacting cells. Many aspects of connexin function, for example cellular transport, plaque assembly and stability, and channel conductivity, are finely tuned and likely involve proteins that bind to connexins' cytoplasmic domains. However, little is known about such regulatory proteins. To identify novel proteins that interact with the COOH-terminal domain of Connexin-43 (Cx43), the most widely expressed connexin family member, we applied a proteomics approach to screen fractions of mouse tissue homogenates for binding partners.Results: Drebrin was recovered as a binding partner of the Cx43 COOH-terminal domain from mouse brain homogenate. Drebrin had previously been described as an actin binding protein that diminishes in brains during Alzheimer's disease. The novel Drebrin-Cx43 interaction identified by proteomics was confirmed by colocalization of endogenous proteins in astrocytes and Vero cells, coimmunoprecipitation, electron microscopy, electrophysiology, coexpression of both proteins with fluorescent tags, and live-cell FRET analysis. Depletion of Drebrin in cells with siRNA results in impaired cell-cell coupling, internalization of gap junctions, and targeting of Cx43 to a degradative pathway.Conclusions: We conclude that Drebrin is required for maintaining Cx43-containing gap junctions in their functional state at the plasma membrane. It is thus possible that Drebrin may interact with gap junctions in zones of cell-cell contacts in a regulated fashion in response to extracellular signals. The rearrangement or disruption of interactions between connexins and the Drebrin-containing submembrane cytoskeleton directs connexins to degradative cellular pathways
Work function of a quasicrystal surface: Icosahedral AlâPdâMn
The work function of a surface is one of its most basic and inïŹuential features. It has long been recognized that work function controls thermionic and ïŹeld emission. The work function of a solid surface affects charge transfer to or from an adsorbate. It inïŹuences the electron tunneling probability between surfaces. It plays a role in quantization of electron states parallel to the surface in metal-supported metallic nanoislands. There is also evidence linking the work function of a metal surface to its friction coefïŹcient
Periodic step arrays on the aperiodic i-Al-Pd-Mn quasicrystal surface at high temperature
We have observed the configuration and motion of surface steps on the aperiodic icosahedral (i-) Al-Pd-Mn quasicrystal using low-energy electron microscopy and scanning tunneling microscopy. As the quasicrystal is cooled from high temperature, bulk vacancies migrate to the surface causing the surface to be etched. Surprisingly, this etching occurs by two types of steps with different heights moving in different directions with different velocities. The steady-state surface morphology is a uniformly spaced rhomboidal step network. This network requires that the layer stacking near the surface deviates from the bulk quasicrystal stacking
Influence of uncorrelated overlayers on the magnetism in thin itinerant-electron films
The influence of uncorrelated (nonmagnetic) overlayers on the magnetic
properties of thin itinerant-electron films is investigated within the
single-band Hubbard model. The Coulomb correlation between the electrons in the
ferromagnetic layers is treated by using the spectral density approach (SDA).
It is found that the presence of nonmagnetic layers has a strong effect on the
magnetic properties of thin films. The Curie temperatures of very thin films
are modified by the uncorrelated overlayers. The quasiparticle density of
states is used to analyze the results. In addition, the coupling between the
ferromagnetic layers and the nonmagnetic layers is discussed in detail. The
coupling depends on the band occupation of the nonmagnetic layers, while it is
almost independent of the number of the nonmagnetic layers. The induced
polarization in the nonmagnetic layers shows a long-range decreasing
oscillatory behavior and it depends on the coupling between ferromagnetic and
nonmagnetic layers.Comment: 9 pages, RevTex, 6 figures, for related work see:
http://orion.physik.hu-berlin.d
Multilab Direct Replication of Flavell, Beach, and Chinsky (1966): Spontaneous Verbal Rehearsal in a Memory Task as a Function of Age
Work by Flavell, Beach, and Chinsky indicated a change in the spontaneous production of overt verbalization behaviors when comparing young children (age 5) with older children (age 10). Despite the critical role that this evidence of a change in verbalization behaviors plays in modern theories of cognitive development and working memory, there has been only one other published near replication of this work. In this Registered Replication Report, we relied on researchers from 17 labs who contributed their results to a larger and more comprehensive sample of children. We assessed memory performance and the presence or absence of verbalization behaviors of young children at different ages and determined that the original pattern of findings was largely upheld: Older children were more likely to verbalize, and their memory spans improved. We confirmed that 5- and 6-year-old children who verbalized recalled more than children who did not verbalize. However, unlike Flavell et al., substantial proportions of our 5- and 6-year-old samples overtly verbalized at least sometimes during the picture memory task. In addition, continuous increase in overt verbalization from 7 to 10 years old was not consistently evident in our samples. These robust findings should be weighed when considering theories of cognitive development, particularly theories concerning when verbal rehearsal emerges and relations between speech and memory
Holding blame at bay? âGene talkâ in family membersâ accounts of schizophrenia aetiology
We provide the first detailed analysis of how, for what purposes and with what consequences people related to someone with a diagnosis of schizophrenia use âgene talk'. The article analyses findings from a qualitative interview study conducted in London and involving 19 participants (mostly women). We transcribed the interviews verbatim and analysed them using grounded theory methods. We analyse how and for what purposes participants mobilized âgene talk' in their affectively freighted encounter with an unknown interviewer. Gene talk served to (re)position blame and guilt, and was simultaneously used imaginatively to forge family history narratives. Family members used âgene talk' to recruit forebears with no psychiatric diagnosis into a family history of mental illness, and presented the origins of the diagnosed family member's schizophrenia as lying temporally before, and hence beyond the agency of the immediate family. Gene talk was also used in attempts to dislodge the distressing figure of the schizophrenia-inducing mother. âGene talk', however, ultimately displaced, rather than resolved, the (self-)blame of many family members, particularly mothers. Our article challenges the commonly expressed view that genetic accounts will absolve family members' sense of (self-)blame in relation to their relative's/relatives' diagnosis
Falling back into gender?: Menâs narratives and practices around first-time fatherhood
This article explores menâs articulations and practices of gender through transition to first-time fatherhood. Using qualitative longitudinal data, menâs antenatal intentions and postnatal practices are explored in this study which replicates earlier research on motherhood. The contemporary context in the UK is one where paternity leave, discourses of caring masculinities and more public displays of fathering involvement appear to offer new possibilities for men. But data analysis shows that whilst opportunities to disrupt gender norms are initially imagined, longer term practices can confirm âpatriarchal habitsâ. The findings illuminate gender being done and undone, at times simultaneously, as the exhaustion and hard work of new parenting is encountered. A retreat into normative behaviours can be a path of least resistance as experiences unfold in an arena where men are found to have available to them a wider repertoire of discursive storylines. Optimistically, some changes in fathering involvement are discernible
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