University of Jyväskylä

About: University of Jyväskylä is a education organization based out in Jyvaskyla, Finland. It is known for research contribution in the topics: Population & Context (language use). The organization has 8066 authors who have published 25168 publications receiving 725033 citations. The organization is also known as: Jyväskylän yliopisto & Kasvatusopillinen korkeakoulu.

Integrin α2β1 Promotes Activation of Protein Phosphatase 2A and Dephosphorylation of Akt and Glycogen Synthase Kinase 3β

Abstract: The integrins are a large family of heterodimeric transmembrane receptors composed of α and β subunits (22). In addition to mediating cell-matrix interactions, integrins have been shown to activate intracellular signaling pathways which, in collaboration with growth factor-induced signals, regulate cellular functions (46). Some integrin signaling cascades are activated via the β subunit cytoplasmic domain, and they are therefore triggered by several integrin heterodimers. These signals include the activation of protein tyrosine kinases of the Src and focal adhesion kinase (FAK) families (9, 47). More-recent studies have revealed signaling events that are activated specifically by an α subunit (19). Integrins may associate with other membrane proteins, such as caveolin-1, and a subset of integrins can activate extracellular signal-related kinase, one of the mitogen-activated protein kinases, via Fyn and Shc (53, 54). Some integrins interact with other membrane proteins to regulate distinct signaling cascades. For example laminin receptor α3β1 associates with tetraspanin proteins and activates phosphatidylinositol-3-kinase (PI-3K) and PI-4K (4). We have shown that α2β1 integrin specifically activates the p38 pathway via a mechanism involving the α2 cytoplasmic tail and Cdc42 (25). The p38 signaling pathway seems to regulate the expression of type I collagen and collagenase-3 (25, 42), and it is required for cell migration on collagen (29). The PI-3K/Akt pathway is activated by a wide range of extracellular stimuli, including the integrins (12), and it has been linked to cell survival (13). Recently it was demonstrated that the different variants of the cytoplasmic domain in the β1 subunit can equally activate Akt (14, 16) and that the binding of α5β1 to fibronectin activates Akt, unlike the binding of α2β1 to monomeric collagen (15). Thus the activation of Akt may be dependent on the integrin α subunit. Reversible phosphorylation of proteins is a major mechanism for the control of cellular signaling pathways and maintenance of homeostasis (21). Although numerous kinases have been implicated in integrin signaling, the function and possible regulation of the corresponding phosphatases are largely unknown. Adhesion of cultured fibroblasts to extracellular matrix proteins has been shown to induce recruitment and activation of SHP-2, a nontransmembrane protein tyrosine phosphatase (39, 51). SHP-2 seems to play an active role in integrin-mediated signaling events, such as cell adhesion and migration (36, 62). Very little is known about the role of protein serine/threonine phosphatases in integrin signaling. Recent data have indicated a positive role for protein serine/threonine phosphatase 2A (PP2A) in integrin inside-out signaling. Inhibition of PP2A activity induces a selective loss of β1 integrins from focal adhesion sites (38) and inhibits cell adhesion (11); in addition PP2A has been shown to colocalize with β1 integrin at adhesion sites (38). However, the role of serine/threonine phosphatases in modulating integrin outside-in signals remains to be studied. Many studies have demonstrated the importance of PP2A in regulating a variety of cellular functions (52). Therefore it is likely that PP2A activity is tightly controlled in vivo. Cell adhesion to three-dimensional (3D) fibrillar collagen, unlike adhesion to monomeric two-dimensional collagen, inhibits cell proliferation in different cell types (15, 20, 30) and induces specific integrin-mediated signals, which regulate gene expression (25, 42, 44). Here, a novel α2β1-mediated signaling mechanism is introduced. Using human primary fibroblasts and human osteosarcoma (Saos-2) cell clones expressing either the wild-type α2 subunit or a signaling-deficient α2/α1 chimera, we have analyzed the ability of α2β1 integrin to regulate signals that have been linked with cell proliferation and survival. We and others have shown that α2β1 integrin is not involved in the regulation of the extracellular signal-related kinase mitogen-activated protein kinase pathway in response to collagen (25, 42, 53). However, here we show that cell adhesion to 3D collagen attenuates Akt and glycogen synthase kinase 3β (GSK3β) phosphorylation by a mechanism involving α2β1-induced activation of PP2A.

Trajectories of Reading Development: A Follow-up From Birth to School Age of Children With and Without Risk for Dyslexia

Abstract: In order to understand why some children are vulnerable to difficulties in their language development and their acquisition of reading skill, the Jyvaskyla Longitudinal Study of Dyslexia followed 200 Finnish children from birth to school age. Half of these children had a family history of reading problems and were considered at risk for dyslexia; the other half were not at risk. A novel analysis, mixture modeling, revealed four subgroups with differential developmental trajectories to early reading. The subgroups who showed either a “dysfluent trajectory” (n = 12; 11 at risk vs. 1 control) or a “declining trajectory” (n = 35; 24 vs. 11) contained more children with familial risk for dyslexia. The subgroup showing an “unexpected trajectory” contained equal numbers of at-risk and non-risk children (n = 67; 33 vs. 34). The subgroup displaying a “typical trajectory” (n = 85, 38 vs. 47) contained more children born without dyslexia risk. This differential development of skills revealed that there are at least three troubled routes along which a child may ultimately encounter difficulties in reading acquisition. The most explicit routes are characterized by problems in either phonological awareness, naming speed, or letter knowledge—problems that increase in severity with age.

Competition for breeding sites and site‐dependent population regulation in a highly colonial seabird, the common guillemot Uria aalge

Abstract: Summary 1. The hypothesis of site-dependent population regulation predicts that birds utilize available nesting sites in a pre-emptive (ideal despotic) manner, leading to density dependence in heterogeneous habitats as poorer sites are used at higher population densities. At small population sizes adaptive site choice protects populations against fluctuations (the buffer effect). 2. Common guillemots Uria aalge (Pontoppidan) breed at high density on sea-cliffs. The population breeding on the Isle of May, Scotland increased by 60% between 1981 and 2000. A good nest-site is a prerequisite for successful breeding and there is much competition for the best sites. Throughout this period, site use correlated with two measures of site quality, and photographs taken in 1936 show that this pattern has been extremely stable. 3. The data indicate declining quality of sites that remain available as the population has increased. Site-dependent regulation was evident in that average breeding success declined over the years, but no declining trend was detected in the best (and most preferred) sites. 4. An individual guillemot generally uses the same nest-site from year to year, but a minority move, usually less than 2 m, between breeding seasons. These movements can be involuntary or voluntary. Involuntarily moving birds that had occupied very good sites before moving often spent several years as non-breeders (floaters) close to their previous site before breeding again, and then occupied poorer sites. Voluntarily moving birds significantly improved their site quality by moving. 5. Birds responded both to the physical site characteristics and to their own experience (breeding failure) when abandoning a site. Their behaviour thus combined aspects of the ‘win-stay, lose-switch’ strategy with direct assessment of site quality. Our data set is inconclusive with respect to the public information hypothesis, i.e. whether birds use conspecific cues of breeding success when settling in a new site.

A comparative analysis of primary teacher professionalism in England and Finland

Abstract: Policy‐makers' conceptions of teacher professionalism currently differ markedly in England and Finland. In England they are shaped by agendas associated with the drive to raise standards and ‘commercialized professionalism’ whilst in Finland they are influenced by notions of ‘teacher empowerment’. This article analyses findings on the theme of teacher professionalism derived from re‐interviewing a sample of English and Finnish teachers in 2001 as a follow‐up to earlier ethnographic research in six schools in each country during 1994–1996. Issues of professionalism are addressed through three broad themes: the impact of curriculum and pedagogical reforms; working together to implement these reforms; and accountability and control. It is argued that in each country teachers' conceptions of their professionalism were undergoing reconstruction. These conceptions were shaped by past and present ideology, policy and practice and displayed multiple and situational dimensions.

Rapidity and transverse-momentum dependence of the inclusive J/psi nuclear modification factor in p-Pb collisions at root s(NN)=5.02 TeV

Abstract: We have studied the transverse-momentum (pT) dependence of the inclusive J/ψ production in p-Pb collisions at √sNN = 5.02 TeV, in three center-of-mass rapidity (ycms) regions, down to zero pT. Results in the forward and backward rapidity ranges (2.03 < ycms < 3.53 and −4.46 < ycms < −2.96) are obtained by studying the J/ψ decay to µ +µ −, while the mid-rapidity region (−1.37 < ycms < 0.43) is investigated by measuring the e+e − decay channel. The pT dependence of the J/ψ production cross section and nuclear modification factor are presented for each of the rapidity intervals, as well as the J/ψ mean pT values. Forward and mid-rapidity results show a suppression of the J/ψ yield, with respect to pp collisions, which decreases with increasing pT. At backward rapidity no significant J/ψ suppression is observed. Theoretical models including a combination of cold nuclear matter effects such as shadowing and partonic energy loss, are in fair agreement with the data, except at forward rapidity and low transverse momentum. The implications of the p-Pb results for the evaluation of cold nuclear matter effects on J/ψ production in Pb-Pb collisions are also discussed.