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Plasmodium motility : actin not actin' like actin

Apicomplexan parasites such as Plasmodium and Toxoplasma display actomyosin-dependent motility in the absence of readily detectable actin polymers. Three recent studies indicate that parasite actin polymers, either harvested from parasites or formed from purified recombinant proteins, are exceptionally short ( approximately 100 nm). We propose that parasite motility could be directed by the transi

A Plasmodium actin-depolymerizing factor that binds exclusively to actin monomers

ADF/cofilins (AC) are essential F- and G-actin binding proteins that modulate microfilament turnover. The genome of Plasmodium falciparum, the parasite causing malaria, contains two members of the AC family. Interestingly, P. falciparum ADF1 lacks the F-actin binding residues of the AC consensus. Reverse genetics in the rodent malaria model system suggest that ADF1 performs vital functions during

Unusual properties of Plasmodium falciparum actin : new insights into microfilament dynamics of apicomplexan parasites

Plasmodium falciparum, the etiologic agent of malaria, is a facultative intracellular parasite of the phylum Apicomplexa. A limited turnover of microfilaments takes place beneath the parasite plasma membrane, but the cytoplasm of apicomplexans is virtually devoid of F-actin. We produced Plasmodium actin in yeast. Purified recombinant Plasmodium actin polymerized inefficiently unless both gelsolin

The role of MeH73 in actin polymerization and ATP hydrolysis

In actin from many species H73 is methylated, but the function of this rare post-translational modification is unknown. Although not within bonding distance, it is located close to the gamma-phosphate of the actin-bound ATP. In most crystal structures of actin, the delta1-nitrogen of the methylated H73 forms a hydrogen bond with the carbonyl of G158. This hydrogen bond spans the gap separating sub

DNA binding to SMC ATPases-trapped for release

The SMC/Rad50/RecN proteins are universal DNA‐associated ABC‐type ATPases with crucial functions in genome maintenance. New insights into Rad50-DNA complex structure and cohesin regulation inspire a speculative look at the entire superfamily. Identification of a continuous DNA binding site across the Rad50 dimer interface (Liu et al, 2016; Seifert et al, 2016) suggests a similar site in cohesin. T

Structure and Function of IGA

In mammals, IgA is the antibody class that is produced in largest quantities. The main producers are plasma cells located in the lamina propria at mucosal surfaces that secrete it as dimers covalently linked to the J chain. Polymeric immunoglobulin receptors (pIgRs) expressed on epithelial cells bind to dimeric IgA molecules and mediate basolateral to apical transcytosis, before IgA is released in

Pupil contagion variation with gaze, arousal, and autistic traits

Pupillary contagion occurs when one's pupil size unconsciously adapts to the pupil size of an observed individual and is presumed to reflect the transfer of arousal. Importantly, when estimating pupil contagion, low level stimuli properties need to be controlled for, to ensure that observations of pupillary changes are due to internal change in arousal rather than the external differences between

Influence of autistic traits and communication role on eye contact behavior during face-to-face interaction

Eye contact is a central component in face-to-face interactions. It is important in structuring communicative exchanges and offers critical insights into others' interests and intentions. To better understand eye contact in face-to-face interactions, we applied a novel, non-intrusive deep-learning-based dual-camera system and investigated associations between eye contact and autistic traits as wel

Visuomotor tracking strategies in children : associations with neurodevelopmental symptoms

Children with neurodevelopmental disorders (NDDs) often display motor problems that may impact their daily lives. Studying specific motor characteristics related to spatiotemporal control may inform us about the mechanisms underlying their challenges. Fifty-eight children with varying neurodevelopmental symptoms load (median age: 5.6 years, range: 2.7-12.5 years) performed an interactive tablet-ba

Self-reported eye contact sensitivity and face processing in chromosome 22q11.2 deletion syndrome

INTRODUCTION: 22q11.2 deletion syndrome (22qDS) has been associated with varying levels of social impairments, and with atypical visual scanning of faces. The present study explored whether self-reported sensitivity to eye contact might be related to these phenomena.METHOD: Individuals with confirmed 22qDS were interviewed about their experience and possible discomfort with eye contact. In cases w

A novel end-to-end dual-camera system for eye gaze synchrony assessment in face-to-face interaction

Quantification of face-to-face interaction can provide highly relevant information in cognitive and psychological science research. Current commercial glint-dependent solutions suffer from several disadvantages and limitations when applied in face-to-face interaction, including data loss, parallax errors, the inconvenience and distracting effect of wearables, and/or the need for several cameras to