Rap1 is a member of the Ras-like small GTPases. Originally the protein was identified in a genome-wide screen for suppressors of Ras transformation, but the mechanism of this reversion remained ...elusive. We have investigated the signalling function of Rap1. We observed that Rap1 is activated by a large variety of stimuli, including growth factors, neurotransmitters and cytokines. Common second messengers like cAMP, diacylglycerol and calcium are mediators of this activation. These messengers activate guanine nucleotide exchange factors (GEFs), the most notable of which is Epac (exchange protein directly activated by cAMP). However, the downstream effectors of Rap1 are less clear. Although direct connections of Rap1 with the serine/threonine kinases Raf1 and B-raf have been reported, we were unable to find functional evidence for an interaction of endogenous Rap1 signalling with the Raf/extracellular-signal-regulated kinase (ERK) pathway. Instead we observe a clear connection of Rap1 with inside-out signalling to integrins. Indeed, introduction of a constitutively active Rap1 as well as Epac induces integrin-mediated cell adhesion, whereas inhibition of Rap1 signalling by the introduction of Rap1GAP (GTPase-activating protein) inhibits inside-out activation of integrins. More importantly, activation of a G(s)-protein-coupled receptor results in integrin-mediated cell adhesion, by a pathway involving Epac and Rap1. From these results, we conclude that one of the functions of receptor-induced Rap1 activation is inside-out regulation of integrins.
BACKGROUND: The aim of the present study was to gain insight into parents' own donor preferences within a system offering the choice between an anonymous and identity-registered donor. A comparison ...was made between recipients choosing for an anonymous donor (AD choosers) and those choosing for an identifiable donor (ID choosers) with regard to their sexual orientation, demographic characteristics, disclosure issues and infertility distress. METHODS: Data from 105 couples (61% heterosexual, 39% lesbian) were registered on a standardized form during implication counselling sessions previous to treatment. RESULTS: Sixty-three per cent of the heterosexual couples and 98% of the lesbian couples had chosen an ID donor. Major differences between ID and AD choosers were identified. Among the ID choosers secrecy towards the child was no option, whereas 83% of the AD choosers did not intend to inform their child. Compared with heterosexual ID choosers, AD choosers were more distressed about their infertility and had a lower educational level. CONCLUSION: Legislation imposing ID donors appears to be acceptable for the majority of this study population. For a vulnerable group of heterosexual couples, who remained secretive about the use of a donor, adaptation to the new system is not self-evident.
In this study some aspects of the vacuum metallization of plastics and composite materials were investigated from an industrial point of view. The study involved the most commonly used substrate ...materials being ABS, PC, PP and a composite (glass fiber/epoxy resin) material. Substrates were subjected to industrially feasible pretreatments such as flame treatment, chemical treatment, mechanical treatment, oxygen plasma and also a lacquer treatment. Surface characterization before and after the pretreatments has been done by atomic force microscopy, X-ray photo-electron spectroscopy and contact angle measurements. An aluminium layer was deposited by magnetron sputtering to nominal thicknesses of 0.1 and 1.0 μm. The adhesion of the metallic layer was studied by the cross-cut test (ISO 2409) and the falling-weight test (ISO 6272), two standardized methods that can be easily performed in an industrial environment. The results indicate that these tests can only be used for a go or no-go decision on the adhesion.
Results from a comparative study investigating 38 donor insemination (DI) Dutch families with 4-8 year old children are presented. The aims of this study were to investigate parents' opinions on the ...issues of confidentiality and donor anonymity, to assess the emotional development of the children, and to examine in DI families the association between secrecy with regard to the use of a donor and the emotional adjustment of the children. The DI families were compared to families with a child conceived by in-vitro fertilization (IVF) and to families with a naturally conceived child. Secrecy appeared to be associated with DI and not with IVF: 74% of the DI parents intended not to inform the child about the way in which she/he was conceived, whereas none of the IVF parents intended to keep the secret. Only one set of DI parents and two sets of IVF parents had actually told the child. As to donor anonymity, a spread of opinions appeared among DI parents; 57% preferred an anonymous donor, 31% would have liked non-identifying information about the donor, 9% preferred the donor's identity to be registered and 3% remained unsure. Parents' major concern was to know more about the medical/genetic background of the donor. Mothers and fathers in the DI families differed in their opinions concerning the issues of confidentiality and donor anonymity: fathers, more often than mothers, were secretive with regard to the use of a donor and husbands, more often than their wives, were in favour of donor anonymity. With regard to the emotional development of the children, more emotional/behavioural problems were revealed among DI children than among children who were naturally conceived. No association was found between secrecy and the emotional/behavioural adjustment of the children.
The calibration and performance of the opposite-side flavour tagging algorithms used for the measurements of time-dependent asymmetries at the LHCb experiment are described. The algorithms have been ...developed using simulated events and optimized and calibrated with
B
+
→
J
/
ψK
+
,
B
0
→
J
/
ψK
∗0
and
B
0
→
D
∗−
μ
+
ν
μ
decay modes with 0.37 fb
−1
of data collected in
pp
collisions at
during the 2011 physics run. The opposite-side tagging power is determined in the
B
+
→
J
/
ψK
+
channel to be (2.10±0.08±0.24) %, where the first uncertainty is statistical and the second is systematic.
A
bstract
Based on data corresponding to an integrated luminosity of 0.37 fb
−1
collected by the LHCb experiment in 2011, the following ratios of branching fractions are measured:
where the first ...uncertainties are statistical and the second systematic. Using the current world average of
and the ratio of the strange to light neutral
B
meson production
f
s
/
f
d
measured by LHCb, we obtain:
The measurements of
,
and
are the most precise to date. The decay mode
is observed for the first time with a significance of more than 5
σ
.
Activation of phosphatidylinositide 3'-OH kinase (PI 3-kinase) is implicated in mediating a variety of growth factor-induced responses, among which are the inactivation of glycogen synthase kinase-3 ...(GSK-3) and the activation of the serine/threonine protein kinase B (PKB). GSK-3 inactivation occurs through phosphorylation of Ser-9, and several kinases, such as protein kinase C, mitogen-activated protein kinase-activated protein kinase-1 (p90(Rsk)), p70(S6kinase), and also PKB have been shown to phosphorylate this site in vitro. In the light of the many candidates to mediate insulin-induced GSK-3 inactivation we have investigated the role of PKB by constructing a PKB mutant that exhibits dominant-negative function (inhibition of growth factor-induced activation of PKB at expression levels similar to wild-type PKB), as currently no such mutant has been reported. We observed that the PKB mutant (PKB-CAAX) acts as an efficient inhibitor of PKB activation and also of insulin-induced GSK-3 regulation. Furthermore, it is shown that PKB and GSK-3 co-immunoprecipitate, indicating a direct interaction between GSK-3 and PKB. An additional functional consequence of this interaction is implicated by the observation that the oncogenic form of PKB, gagPKB induces a cellular relocalization of GSK-3 from the cytosolic to the membrane fraction. Our results demonstrate that PKB activation is both necessary and sufficient for insulin-induced GSK-3 inactivation and establish a linear pathway from insulin receptor to GSK-3. Regulation of GSK-3 by PKB is likely through direct interaction, as both proteins co-immunoprecipitate. This interaction also resulted in a translocation of GSK-3 to the membrane in cells expressing transforming gagPKB.
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