Publications by authors named "Lappalainen P"

Insomnia, i.e., difficulty falling asleep or staying asleep, is a common condition that is connected to many psychological and physical problems.

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This study investigated the impact of online psychological flexibility training and support provided by peers on self-rated health (SRH) and health-related quality of life (HRQoL) among adults with overweight. It was a secondary analysis of a single-arm multi-center intervention study that was conducted in a real-life context. In a 2-years acceptance and commitment therapy (ACT) lifestyle intervention, participants ( = 177) engaged in online ACT activities while receiving support from trained peers.

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Dynamic actin filament remodeling is crucial for a plethora of fundamental cell biological processes, ranging from cell division and migration to cell communication, intracellular trafficking or tissue development. Cytochalasin B and -D are fungal secondary metabolites frequently used for interference with such processes. Although generally assumed to block actin filament polymerization at their rapidly growing barbed ends and compete with regulators at these sites, our molecular understanding of their precise effects in dynamic actin structures is scarce.

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Objective: Persistent physical symptoms (PPS) represent a major health problem affecting daily functioning. This RCT aimed to examine whether a guided Internet-based treatment based on acceptance and commitment therapy (ACT) provided additional benefits compared to Treatment as Usual (TAU) in reducing somatic complaints and psychological distress in adults with PPS.

Methods: A total of 103 adults with PPS related to indoor environments, chronic fatigue or both conditions were assigned to receive either either a 14-week intervention (video-based case conceptualization + Internet-based ACT) combined with TAU (iACT + TAU; n = 50) or TAU alone (n = 53).

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Focal adhesions (FAs) connect inner workings of cell to the extracellular matrix to control cell adhesion, migration and mechanosensing. Previous studies demonstrated that FAs contain three vertical layers, which connect extracellular matrix to the cytoskeleton. By using super-resolution iPALM microscopy, we identify two additional nanoscale layers within FAs, specified by actin filaments bound to tropomyosin isoforms Tpm1.

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Diseases caused by Leishmania and Trypanosoma parasites are a major health problem in tropical countries. Because of their complex life cycle involving both vertebrate and insect hosts, and >1 billion years of evolutionarily distance, the cell biology of trypanosomatid parasites exhibits pronounced differences to animal cells. For example, the actin cytoskeleton of trypanosomatids is divergent when compared with other eukaryotes.

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Familial cardiomyopathy in pediatric stages is a poorly understood presentation of heart disease in children that is attributed to pathogenic mutations. Through exome sequencing, we report a homozygous variant in tropomodulin 1 (TMOD1; c.565C>T, p.

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Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry mechanism has been explored, little is known about how SARS-CoV-2 regulates the subcellular structural remodeling to invade multiple organs and cell types. Here, we unveil how SARS-CoV-2 boosts and utilizes filopodia to enter the target cells by real-time imaging. Using SARS-CoV-2 single virus-like particle (VLP) tracking in live cells and sparse deconvolution algorithm, we uncover that VLPs utilize filopodia to reach the entry site in two patterns, "surfing" and "grabbing", which avoid the virus from randomly searching on the plasma membrane.

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Introduction: Relatively little is known about individual differences in adolescent psychological flexibility and its associations with symptoms of stress and depression. This study examined different profiles of adolescent stress and depressive symptoms and their associations with developing psychological flexibility before the critical educational transition.

Methods: The data were derived from a general sample of 740 Finnish ninth-grade adolescents (M  = 15.

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Intracellular organization is largely mediated by actin turnover. Cellular actin networks continuously assemble and disassemble, while maintaining their overall appearance. This behavior, called "dynamic steady state," allows cells to sense and adapt to their environment.

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Metastasis-suppressor 1 (MTSS1) is a membrane-interacting scaffolding protein that regulates the integrity of epithelial cell-cell junctions and functions as a tumor suppressor in a wide range of carcinomas. MTSS1 binds phosphoinositide-rich membranes through its I-BAR domain and is capable of sensing and generating negative membrane curvature in vitro. However, the mechanisms by which MTSS1 localizes to intercellular junctions in epithelial cells and contributes to their integrity and maintenance have remained elusive.

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Article Synopsis
  • - The actin cytoskeleton is essential for various cellular functions like cell movement, shape change, and division, with actin filaments having different structures to support these processes
  • - Tropomyosin proteins play a crucial role in regulating the behavior of actin filaments and interacting with other proteins, but the details of how they function together have not been fully understood
  • - By using cryogenic electron microscopy, researchers discovered that two types of tropomyosin (Tpm1.6 and Tpm3.2) bind to actin filaments without changing their shape, but take different paths along the filament, explaining their distinct roles in activating myosin and preventing the breakdown of actin filaments by other proteins.
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Background: Although some adolescents managed to cope well with the challenges brought on by the COVID-19 pandemic, the well-being of many was adversely affected due to school closures, distance education, restrictions on gathering with friends, and limited access to mental health services. Many adolescents reported increased anxiety and depression as well as decreased psychological wellbeing due to the pandemic. Consequently, there is a need for psychological support that exceeds the strained resources available to schools to support young people during times of crisis and societal pressure.

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Studies of the effects of the COVID-19 pandemic have shown that this health emergency has affected especially young people. Supporting the well-being of children is thus particularly urgent. However, the high prevalence of ill-being among children requires novel approaches to providing help.

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Filopodia are actin-rich membrane protrusions essential for cell morphogenesis, motility, and cancer invasion. How cells control filopodium initiation on the plasma membrane remains elusive. We performed experiments in cellulo, in vitro, and in silico to unravel the mechanism of filopodium initiation driven by the membrane curvature sensor IRSp53 (insulin receptor substrate protein of 53 kDa).

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Contractile actomyosin bundles are key force-producing and mechanosensing elements in muscle and non-muscle tissues. Whereas the organization of muscle myofibrils and mechanism regulating their contractility are relatively well-established, the principles by which myosin-II activity and force-balance are regulated in non-muscle cells have remained elusive. We show that Caldesmon, an important component of smooth muscle and non-muscle cell actomyosin bundles, is an elongated protein that functions as a dynamic cross-linker between myosin-II and tropomyosin-actin filaments.

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Polymerization of actin filaments against membranes produces force for numerous cellular processes, such as migration, morphogenesis, endocytosis, phagocytosis and organelle dynamics. Consequently, aberrant actin cytoskeleton dynamics are linked to various diseases, including cancer, as well as immunological and neurological disorders. Understanding how actin filaments generate forces in cells, how force production is regulated by the interplay between actin-binding proteins and how the actin-regulatory machinery responds to mechanical load are at the heart of many cellular, developmental and pathological processes.

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Actin polymerization generates forces for cellular processes throughout the eukaryotic kingdom, but our understanding of the 'ancient' actin turnover machineries is limited. We show that, despite > 1 billion years of evolution, pathogenic Leishmania major parasite and mammalian actins share the same overall fold and co-polymerize with each other. Interestingly, Leishmania harbors a simple actin-regulatory machinery that lacks cofilin 'cofactors', which accelerate filament disassembly in higher eukaryotes.

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Objective: This study investigated the roles of adherence and usage activity in adolescents' ( = 161) gains during a 5-week web intervention program based on acceptance and commitment therapy (ACT).

Method: Program adherence was calculated as adherence percentage in relation to intended usage, whereas completion percentage, usage time, and usage weeks were used as indicators for usage activity. Subjective well-being was measured by self-reported life satisfaction and stress before and after the intervention.

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The actomyosin cytoskeleton serves as a key regulator of the integrity and remodeling of epithelial barriers by controlling assembly and functions of intercellular junctions and cell-matrix adhesions. Although biochemical mechanisms that regulate the activity of non-muscle myosin II (NM-II) in epithelial cells have been extensively investigated, little is known about assembly of the contractile myosin structures at the epithelial adhesion sites. UNC-45A is a cytoskeletal chaperone that is essential for proper folding of NM-II heavy chains and myofilament assembly.

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Article Synopsis
  • Immune evasion by Borrelia, which causes diseases like relapsing fever and Lyme disease, is largely facilitated through the acquisition of the host's complement inhibitor Factor H (FH).
  • Researchers determined the 2.2 Å crystal structure of FhbA from Borrelia hermsii in complex with FH, uncovering how it helps the bacteria escape immune responses.
  • The study also identified a family of FhbA-related proteins across different Borrelia species, which share a conserved mechanism for binding FH, potentially leading to new strategies for combating their virulence and resistance to the immune system.
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Parents of children with autism spectrum disorder and other disabilities report high levels of distress, but systematically evaluated interventions are few. This study aimed to evaluate the feasibility of a novel, manualized Acceptance and Commitment Therapy group intervention (Navigator ACT) in a sample of 94 parents of children with disabilities. Feasibility was measured by treatment completion, credibility, and satisfaction, and preliminary outcomes by using self-rating scales administered at the baseline, post-intervention, and follow-up.

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