scholarly journals Plastin Family of Actin-Bundling Proteins: Its Functions in Leukocytes, Neurons, Intestines, and Cancer

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Hiroto Shinomiya
Keyword(s):  
Vital Role ◽  
Protein Family ◽  
Actin Binding ◽  
Animal Cells ◽  
Cell Lineages ◽  
Binding Domains ◽  
Evolutionarily Conserved ◽  
Ef Hand ◽  
Solid Tissues ◽  
The Brain

Sophisticated regulation of the actin cytoskeleton by a variety of actin-binding proteins is essential for eukaryotic cells to perform their diverse functions. The plastin (also know, as fimbrin) protein family belongs to actin-bundling proteins, and the protein family is evolutionarily conserved and expressed in yeast, plant, and animal cells. Plastins are characterized by EF-hand Ca2+-binding domains and actin-binding domains and can cross-link actin filaments into higher-order assemblies like bundles. Three isoforms have been identified in mammals. T-plastin is expressed in cells from solid tissues, such as neurons in the brain. I-plastin expression is restricted to intestine and kidney; the isoform plays a vital role in the function of absorptive epithelia in these organs. L-plastin is expressed in hematopoietic cell lineages and in many types of cancer cells; the isoform is thus considered to be a useful biomarker for cancer.

scholarly journals Interactions among a Fimbrin, a Capping Protein, and an Actin-depolymerizing Factor in Organization of the Fission Yeast Actin Cytoskeleton

2001 ◽  
Vol 12 (11) ◽  
pp. 3515-3526 ◽  
Author(s):  
Kentaro Nakano ◽  
Kazuomi Satoh ◽  
Akeshi Morimatsu ◽  
Masaaki Ohnuma ◽  
Issei Mabuchi
Keyword(s):  
Actin Cytoskeleton ◽  
Fission Yeast ◽  
Actin Binding ◽  
Cell Cortex ◽  
Cross Linking ◽  
Actin Depolymerizing Factor ◽  
Binding Domains ◽  
Ef Hand ◽  
Actin Cables

We report studies of the fission yeast fimbrin-like protein Fim1, which contains two EF-hand domains and two actin-binding domains (ABD1 and ABD2). Fim1 is a component of both F-actin patches and the F-actin ring, but not of F-actin cables. Fim1 cross-links F-actin in vitro, but a Fim1 protein lacking either EF-hand domains (Fim1A12) or both the EF-hand domains and ABD1 (Fim1A2) has no actin cross-linking activity. Overexpression of Fim1 induced the formation of F-actin patches throughout the cell cortex, whereas the F-actin patches disappear in cells overexpressing Fim1A12 or Fim1A2. Thus, the actin cross-linking activity of Fim1 is probably important for the formation of F-actin patches. The overexpression of Fim1 also excluded the actin-depolymerizing factor Adf1 from the F-actin patches and inhibited the turnover of actin in these structures. Thus, Fim1 may function in stabilizing the F-actin patches. We also isolated the gene encoding Acp1, a subunit of the heterodimeric F-actin capping protein.fim1 acp1 double null cells showed more severe defects in the organization of the actin cytoskeleton than those seen in each single mutant. Thus, Fim1 and Acp1 may function in a similar manner in the organization of the actin cytoskeleton. Finally, genetic studies suggested that Fim1 may function in cytokinesis in cooperation with Cdc15 (PSTPIP) and Rng2 (IQGAP), respectively.

scholarly journals Analysis of the conformation and ligand-binding properties of the activation segment of pig procarboxypeptidase A

1988 ◽  
Vol 251 (3) ◽  
pp. 901-905 ◽  
Author(s):  
M Vilanova ◽  
J Vendrell ◽  
C M Cuchillo ◽  
F X Avilés
Keyword(s):  
Ligand Binding ◽  
Spectral Properties ◽  
Protein Family ◽  
Binding Properties ◽  
Binding Domains ◽  
Carbocyanine Dye ◽  
Previous Hypothesis ◽  
Ef Hand ◽  
Activation Segment

The isolated activation segment of pig procarboxypeptidase A binds two Tb3+ ions in a strong and specific way. In contrast, the binding of Ca2+, Cd2+ and Mg2+ is weak. The binding of Tb3+ increases the resistance of the isolated activation segment against proteolysis and competes for the binding of the carbocyanine dye Stains-All. This dye forms complexes with the activation segment showing spectral properties similar to those observed with EF-hand structures. The presented results support a previous hypothesis on the existence of two regions in the activation segment of pancreatic procarboxypeptidases structurally related to Ca2+-binding domains of the EF-hand protein family.

Breaking the code: Ca2+ sensors in plant signalling

2009 ◽  
Vol 425 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Thomas A. DeFalco ◽  
Kyle W. Bender ◽  
Wayne A. Snedden
Keyword(s):  
Conformational Changes ◽  
Current Knowledge ◽  
Second Messengers ◽  
Large Family ◽  
Vital Role ◽  
Calcium Dependent ◽  
Evolutionarily Conserved ◽  
Ef Hand ◽  
Dependent Protein ◽  
Calcium Dependent Protein Kinases

Ca2+ ions play a vital role as second messengers in plant cells during various developmental processes and in response to environmental stimuli. Plants have evolved a diversity of unique proteins that bind Ca2+ using the evolutionarily conserved EF-hand motif. The currently held hypothesis is that these proteins function as Ca2+ sensors by undergoing conformational changes in response to Ca2+-binding that facilitate their regulation of target proteins and thereby co-ordinate various signalling pathways. The three main classes of these EF-hand Ca2+sensors in plants are CaMs [calmodulins; including CMLs (CaM-like proteins)], CDPKs (calcium-dependent protein kinases) and CBLs (calcineurin B-like proteins). In the plant species examined to date, each of these classes is represented by a large family of proteins, most of which have not been characterized biochemically and whose physiological roles remain unclear. In the present review, we discuss recent advances in research on CaMs and CMLs, CDPKs and CBLs, and we attempt to integrate the current knowledge on the different sensor classes into common physiological themes.

Three-Dimensional reconstruction of isolated centrosomes by automated electron tomography

1994 ◽  
Vol 52 ◽  
pp. 310-311
Author(s):  
M.B. Braunfeld ◽  
M. Moritz ◽  
B.M. Alberts ◽  
J.W. Sedat ◽  
D.A. Agard
Keyword(s):  
Electron Tomography ◽  
Three Dimensional ◽  
Vital Role ◽  
Complex Nature ◽  
Animal Cells ◽  
Microtubule Organizing Center ◽  
Nucleation Sites ◽  
Dimensional Reconstruction ◽  
Organizing Center ◽  
Resolution Model

In animal cells, the centrosome functions as the primary microtubule organizing center (MTOC). As such the centrosome plays a vital role in determining a cell's shape, migration, and perhaps most importantly, its division. Despite the obvious importance of this organelle little is known about centrosomal regulation, duplication, or how it nucleates microtubules. Furthermore, no high resolution model for centrosomal structure exists.We have used automated electron tomography, and reconstruction techniques in an attempt to better understand the complex nature of the centrosome. Additionally we hope to identify nucleation sites for microtubule growth.Centrosomes were isolated from early Drosophila embryos. Briefly, after large organelles and debris from homogenized embryos were pelleted, the resulting supernatant was separated on a sucrose velocity gradient. Fractions were collected and assayed for centrosome-mediated microtubule -nucleating activity by incubating with fluorescently-labeled tubulin subunits. The resulting microtubule asters were then spun onto coverslips and viewed by fluorescence microscopy.

scholarly journals Isolation and properties of two actin-binding domains in gelsolin.

1985 ◽  
Vol 260 (28) ◽  
pp. 15232-15238 ◽  
Author(s):  
D J Kwiatkowski ◽  
P A Janmey ◽  
J E Mole ◽  
H L Yin
Keyword(s):  
Actin Binding ◽  
Binding Domains

scholarly journals Evolution, expression and functional analysis of cultivated allotetraploid cotton DIR genes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhengwen Liu ◽  
Xingfen Wang ◽  
Zhengwen Sun ◽  
Yan Zhang ◽  
Chengsheng Meng ◽  
...  
Keyword(s):  
Gene Family ◽  
Stress Responses ◽  
Rapid Evolution ◽  
Gene Clusters ◽  
Vital Role ◽  
Fiber Development ◽  
Rna Seq ◽  
Evolutionarily Conserved ◽  
Cell Wall Development ◽  
Tandem Duplications

Abstract Background Dirigent (DIR) proteins mediate regioselectivity and stereoselectivity during lignan biosynthesis and are also involved in lignin, gossypol and pterocarpan biosynthesis. This gene family plays a vital role in enhancing stress resistance and in secondary cell-wall development, but systematical understanding is lacking in cotton. Results In this study, 107 GbDIRs and 107 GhDIRs were identified in Gossypium barbadense and Gossypium hirsutum, respectively. Most of these genes have a classical gene structure without intron and encode proteins containing a signal peptide. Phylogenetic analysis showed that cotton DIR genes were classified into four distinct subfamilies (a, b/d, e, and f). Of these groups, DIR-a and DIR-e were evolutionarily conserved, and segmental and tandem duplications contributed equally to their formation. In contrast, DIR-b/d mainly expanded by recent tandem duplications, accompanying with a number of gene clusters. With the rapid evolution, DIR-b/d-III was a Gossypium-specific clade involved in atropselective synthesis of gossypol. RNA-seq data highlighted GhDIRs in response to Verticillium dahliae infection and suggested that DIR gene family could confer Verticillium wilt resistance. We also identified candidate DIR genes related to fiber development in G. barbadense and G. hirsutum and revealed their differential expression. To further determine the involvement of DIR genes in fiber development, we overexpressed a fiber length-related gene GbDIR78 in Arabidopsis and validated its function in trichomes and hypocotyls. Conclusions These findings contribute novel insights towards the evolution of DIR gene family and provide valuable information for further understanding the roles of DIR genes in cotton fiber development as well as in stress responses.

scholarly journals Nuclear Import of TFIIB Is Mediated by Kap114p, a Karyopherin with Multiple Cargo-binding Domains

2005 ◽  
Vol 16 (7) ◽  
pp. 3200-3210 ◽  
Author(s):  
Jennifer L. Hodges ◽  
Jennifer H. Leslie ◽  
Nima Mosammaparast ◽  
Yurong Guo ◽  
Jeffrey Shabanowitz ◽  
...  
Keyword(s):  
Nuclear Import ◽  
Binding Sites ◽  
Binding Domains ◽  
Transcription Factor Iib ◽  
General Transcription Factor ◽  
Proteomic Approach ◽  
Evolutionarily Conserved ◽  
Import And Export ◽  
Transport Factors

Nuclear import and export is mediated by an evolutionarily conserved family of soluble transport factors, the karyopherins (referred to as importins and exportins). The yeast karyopherin Kap114p has previously been shown to import histones H2A and H2B, Nap1p, and a component of the preinitiation complex (PIC), TBP. Using a proteomic approach, we have identified several potentially new cargoes for Kap114p. These cargoes include another PIC component, the general transcription factor IIB or Sua7p, which interacted directly with Kap114p. Consistent with its role as a Sua7p import factor, deletion of KAP114 led to specific mislocalization of Sua7p to the cytoplasm. An interaction between Sua7p and TBP was also detected in cytosol, raising the possibility that both Sua7p and TBP can be coimported by Kap114p. We have also shown that Kap114p possesses multiple overlapping binding sites for its partners, Sua7p, Nap1p, and H2A and H2B, as well as RanGTP and nucleoporins. In addition, we have assembled an in vitro complex containing Sua7p, Nap1p, and histones H2A and H2B, suggesting that this Kap may import several proteins simultaneously. The import of more than one cargo at a time would increase the efficiency of each import cycle and may allow the regulation of coimported cargoes.

scholarly journals Synaptic and epidermal accumulations of human acetylcholinesterase are encoded by alternative 3'-terminal exons.

1995 ◽  
Vol 15 (6) ◽  
pp. 2993-3002 ◽  
Author(s):  
S Seidman ◽  
M Sternfeld ◽  
R Ben Aziz-Aloya ◽  
R Timberg ◽  
D Kaufer-Nachum ◽  
...  
Keyword(s):  
Neuromuscular Junctions ◽  
Gene Transcript ◽  
Dna Encoding ◽  
Tissue Specific ◽  
Evolutionarily Conserved ◽  
Low Salt ◽  
Catalytically Active ◽  
Specific Accumulation ◽  
The Brain ◽  
Muscle Ache

Tissue-specific heterogeneity among mammalian acetylcholinesterases (AChE) has been associated with 3' alternative splicing of the primary AChE gene transcript. We have previously demonstrated that human AChE DNA encoding the brain and muscle AChE form and bearing the 3' exon E6 (ACHE-E6) induces accumulation of catalytically active AChE in myotomes and neuromuscular junctions (NMJs) of 2- and 3-day-old Xenopus embryos. Here, we explore the possibility that the 3'-terminal exons of two alternative human AChE cDNA constructs include evolutionarily conserved tissue-recognizable elements. To this end, DNAs encoding alternative human AChE mRNAs were microinjected into cleaving embryos of Xenopus laevis. In contrast to the myotomal expression demonstrated by ACHE-E6, DNA carrying intron 14 and alternative exon E5 (ACHE-I4/E5) promoted punctuated staining of epidermal cells and secretion of AChE into the external medium. Moreover, ACHE-E6-injected embryos displayed enhanced NMJ development, whereas ACHE-I4/E5-derived enzyme was conspicuously absent from muscles and NMJs and its expression in embryos had no apparent effect on NMJ development. In addition, cell-associated AChE from embryos injected with ACHE-I4/E5 DNA was biochemically distinct from that encoded by the muscle-expressible ACHE-E6, displaying higher electrophoretic mobility and greater solubility in low-salt buffer. These findings suggest that alternative 3'-terminal exons dictate tissue-specific accumulation and a particular biological role(s) of AChE, associate the 3' exon E6 with NMJ development, and indicate the existence of a putative secretory AChE form derived from the alternative I4/E5 AChE mRNA.

scholarly journals Cul4-Ddb1 ubiquitin ligases facilitate DNA replication-coupled sister chromatid cohesion through regulation of cohesin acetyltransferase Esco2

2018 ◽  
Author(s):  
Haitao Sun ◽  
Jiaxin Zhang ◽  
Jingjing Zhang ◽  
Zhen Li ◽  
Qinhong Cao ◽  
...  
Keyword(s):  
Dna Replication ◽  
Ubiquitin Ligase ◽  
Sister Chromatid ◽  
Critical Role ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Ligases ◽  
Sister Chromatid Cohesion ◽  
Vital Role ◽  
Chromatid Cohesion ◽  
Evolutionarily Conserved

AbstractCohesin acetyltransferases Esco1 and Esco2 play a vital role in establishing sister chromatid cohesion. How Esco1 and Esco2 are controlled to achieve this in a DNA replication-coupled manner remains unclear in higher eukaryotes. Here we show that Cul4-RING ligases (CRL4s) play a critical role in sister chromatid cohesion in human cells. Depletion of Cul4A, Cul4B or Ddb1 subunits substantially reduces normal cohesion efficiency. We also show that Mms22L, a vertebrate ortholog of yeast Mms22, is one of Ddb1 and Cul4-associated factors (DCAFs) involved in cohesion. Several lines of evidence suggest a selective interaction of CRL4s with Esco2, but not Esco1. Depletion of either CRL4s or Esco2 causes a defect in Smc3 acetylation which can be rescued by HDAC8 inhibition. More importantly, both CRL4s and PCNA act as mediators for efficiently stabilizing Esco2 on chromatin and catalyzing Smc3 acetylation. Taken together, we propose an evolutionarily conserved mechanism in which CRL4s and PCNA regulate Esco2-dependent establishment of sister chromatid cohesion.Author summaryWe identified human Mms22L as a substrate specific adaptor of Cul4-Ddb1 E3 ubiquitin ligase. Downregulation of Cul4A, Cul4B or Ddb1 subunit causes reduction of acetylated Smc3, via interaction with Esco2 acetyltransferase, and then impairs sister chromatid cohesion in 293T cells. We found functional complementation between Cul4-Ddb1-Mms22L E3 ligase and Esco2 in Smc3 acetylation and sister chromatid cohesion. Interestingly, both Cul4-Ddb1 E3 ubiquitin ligase and PCNA contribute to Esco2 mediated Smc3 acetylation. To summarise, we demonstrated an evolutionarily conserved mechanism in which Cul4-Ddb1 E3 ubiquitin ligases and PCNA regulate Esco2-dependent establishment of sister chromatid cohesion.

scholarly journals Brain-inspired model for decision-making in the selection of beneficial information patterns among signals received by an unpredictable information-development environment

2021 ◽  
Author(s):  
Alireza Asgari ◽  
yvan beauregard
Keyword(s):  
Artificial Intelligence ◽  
Decision Making ◽  
Health And Safety ◽  
Vital Role ◽  
Successful Implementation ◽  
Development Environment ◽  
Brain Functions ◽  
Operational Costs ◽  
Industrial Operations ◽  
The Brain

With its diversification in products and services, today’s marketplace makes competition wildly dynamic and unpredictable for industries. In such an environment, daily operational decision-making has a vital role in producing value for products and services while avoiding the risk of loss and hazard to human health and safety. However, it makes a large portion of operational costs for industries. The main reason is that decision-making belongs to the operational tasks dominated by humans. The less involvement of humans, as a less controllable entity, in industrial operation could also favorable for improving workplace health and safety. To this end, artificial intelligence is proposed as an alternative to doing human decision-making tasks. Still, some of the functional characteristics of the brain that allow humans to make decisions in unpredictable environments like the current industry, especially knowledge generalization, are challenging for artificial intelligence. To find an applicable solution, we study the principles that underlie the human brain functions in decision-making. The relative base functions are realized to develop a model in a simulated unpredictable environment for a decision-making system that could decide which information is beneficial to choose. The method executed to build our model's neuronal interactions is unique that aims to mimic some simple functions of the brain in decision-making. It has the potential to develop for systems acting in the higher abstraction levels and complexities in real-world environments. This system and our study will help to integrate more artificial intelligence in industrial operations and settings. The more successful implementation of artificial intelligence will be the steeper decreasing operational costs and risks.

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