[Influenza vaccines dispensed in community pharmacies during the 2010-2011 flu season]. / Vaccins antigrippaux délivrés dans les officines publiques durant la saison 2010-2011.

In this article we consider the delivery of influenza vaccines in the Belgian communiy pharmacies during the influenza season 2010-2011. We compare this season with the previous influenza seasons and consider the age distribution the flu-vaccinated patients. The vaccination rate of the entire population is compared to the vaccination rate among the risk group of diabetic patients. Also the market introduction of intradermal vaccinations in investigated.

The role of Rap1 in integrin-mediated cell adhesion.

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.

RalGEF2, a pleckstrin homology domain containing guanine nucleotide exchange factor for Ral.

Ral is a ubiquitously expressed Ras-like small GTPase. Several guanine nucleotide exchange factors for Ral have been identified, including members of the RalGDS family, which exhibit a Ras binding domain and are regulated by binding to RasGTP. Here we describe a novel type of RalGEF, RalGEF2. This guanine nucleotide exchange factor has a characteristic Cdc25-like catalytic domain at the N terminus and a pleckstrin homology (PH) domain at the C terminus. RalGEF2 is able to activate Ral both in vivo and in vitro. Deletion of the PH domain results in an increased cytoplasmic localization of the protein and a corresponding reduction in activity in vivo, suggesting that the PH domain functions as a membrane anchor necessary for optimal activity in vivo.

Essential role for protein kinase B (PKB) in insulin-induced glycogen synthase kinase 3 inactivation. Characterization of dominant-negative mutant of PKB.

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.