scholarly journals Map7D2 and Map7D1 facilitate MT stabilization through distinct mechanisms to control cell motility and neurite outgrowth

2021 ◽  
Author(s):  
Koji Kikuchi ◽  
Yasuhisa Sakamoto ◽  
Akiyoshi Uezu ◽  
Hideyuki Yamamoto ◽  
Kei-ichiro Ishiguro ◽  
...  
Keyword(s):  
Cell Motility ◽  
Neurite Outgrowth ◽  
Control Cell ◽  
Regulatory Mechanisms ◽  
Acetylated Tubulin ◽  
Family Protein ◽  
Associated Proteins ◽  
Direct Binding ◽  
The Brain

Microtubule (MT) dynamics are modulated through the coordinated action of various MT-associated proteins (MAPs). However, the regulatory mechanisms underlying MT dynamics remain unclear. Herein, we show that MAP7 family protein Map7D2 facilitates MT stabilization to control cell motility and neurite outgrowth. Map7D2, was highly expressed in the brain and testis, directly bound to MTs through its N-terminal half similarly to Map7, and promoted MT stabilization in vitro. Map7D2 localized prominently to the centrosome and partially on MTs in N1-E115 mouse glioblastoma cells, which expresses two of the four MAP7 family members, Map7D2 and Map7D1. Map7D2 loss decreased the intensity of MTs without affecting stable MT markers acetylated and detyrosinated tubulin, suggesting that Map7D2 stabilizes MTs via direct binding. In addition, Map7D2 loss increased the rate of random cell migration and neurite outgrowth, presumably by disturbing the balance between MT stabilization and destabilization. The other MAP7 family protein expressed in N1-E115, Map7D1, exhibited similar subcellular localization and gene knock-down phenotypes. However, in contrast to Map7D2, Map7D1 was required for the maintenance of acetylated tubulin levels. Taken together, our data suggest that Map7D2 and Map7D1 facilitate MT stabilization through distinct mechanisms for the control of cell motility and neurite outgrowth.

scholarly journals FAK promotes recruitment of talin to nascent adhesions to control cell motility

2012 ◽  
Vol 196 (2) ◽  
pp. 223-232 ◽  
Author(s):  
Christine Lawson ◽  
Ssang-Taek Lim ◽  
Sean Uryu ◽  
Xiao Lei Chen ◽  
David A. Calderwood ◽  
...  
Keyword(s):  
Cell Migration ◽  
Cell Motility ◽  
Control Cell ◽  
Integrin Receptors ◽  
Independent Manner ◽  
Continuous Formation ◽  
Adhesion Sites ◽  
Matrix Cell ◽  
Associated Proteins ◽  
Direct Binding

Cell migration is a dynamic process that involves the continuous formation, maturation, and turnover of matrix–cell adhesion sites. New (nascent) adhesions form at the protruding cell edge in a tension-independent manner and are comprised of integrin receptors, signaling, and cytoskeletal-associated proteins. Integrins recruit focal adhesion kinase (FAK) and the cytoskeletal protein talin to nascent adhesions. Canonical models support a role for talin in mediating FAK localization and activation at adhesions. Here, alternatively, we show that FAK promotes talin recruitment to nascent adhesions occurring independently of talin binding to β1 integrins. The direct binding site for talin on FAK was identified, and a point mutation in FAK (E1015A) prevented talin association and talin localization to nascent adhesions but did not alter integrin-mediated FAK recruitment and activation at adhesions. Moreover, FAK E1015A inhibited cell motility and proteolytic talin cleavage needed for efficient adhesion dynamics. These results support an alternative linkage for FAK–talin interactions within nascent adhesions essential for the control of cell migration.

scholarly journals Nerve growth factor-induced neurite outgrowth in PC12 cells involves the coordinate induction of microtubule assembly and assembly-promoting factors.

1985 ◽  
Vol 101 (5) ◽  
pp. 1799-1807 ◽  
Author(s):  
D G Drubin ◽  
S C Feinstein ◽  
E M Shooter ◽  
M W Kirschner
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Time Course ◽  
Microtubule Assembly ◽  
Nerve Growth ◽  
Peripheral Neurons ◽  
Associated Proteins

Nerve growth factor (NGF) regulates the microtubule-dependent extension and maintenance of axons by some peripheral neurons. We show here that one effect of NGF is to promote microtubule assembly during neurite outgrowth in PC12 cells. Though NGF causes an increase in total tubulin levels, the formation of neurites and the assembly of microtubules follow a time course completely distinct from that of the tubulin induction. The increases in microtubule mass and neurite extension closely parallel 10- and 20-fold inductions of tau and MAP1, proteins shown previously to promote microtubule assembly in vitro. When NGF is removed from PC12 cells, neurites disappear, microtubule mass decreases, and both microtubule-associated proteins return to undifferentiated levels. These data suggest that the induction of tau and MAP1 in response to NGF promotes microtubule assembly and that these factors are therefore key regulators of neurite outgrowth.

The effect of cytoskeletal protein mutations on cell motility and morphogenesis

1992 ◽  
Vol 50 (1) ◽  
pp. 594-595
Author(s):  
David A. Knecht
Keyword(s):  
Cell Motility ◽  
Actin Filaments ◽  
Cytoskeletal Proteins ◽  
Cross Linking ◽  
Cytoskeletal Protein ◽  
Homologous Gene ◽  
Complex Interactions ◽  
Associated Proteins ◽  
Protein Mutations

The cortical cytoskeleton of eukaryotic cells is composed of actin filaments and a variety of associated proteins. The polymerization, depolymerization, cross-linking and bundling of these filaments, are presumed to be intimately involved in such processes as cell motility, cell adhesion and cell shape. In developing systems, all of these processes are involved in the morphogenetic mechanisms that shape tissues, organs and organisms.We are investigating the complex interactions among cytoskeletal proteins using the simple eukaryotic amoebae, Dictyostelium discoideum. Our approach is to determine the function of the components of the cytoskeleton by creating mutants lacking particular proteins, or containing specific alterations in these proteins. Mutants lacking myosin heavy chain have been created using antisense RNA and homologous gene targetting. These cells have alterations in their shape and movement, and are incapable of accomplishing normal morphogenesis. Another cytoskeletal protein is ABP-120, which is capable of cross-linking actin filaments into orthogonal arrays, leading to the formation of an actin gel in vitro. ABP-120 is found in newly formed pseudopods extended during the chemotactic respose to extracellular cAMP. Mutants lacking this protein have been created by disruption of the chromosomal gene with a transformation vector. These cells are not as dramatically affected as the myosin mutants, but have clear alterations in their motility and in the pathway of responses in the cytoskeleton that correlate with the expected function of this protein. Mutations in several other cytoskeletal genes are currently being constructed.

scholarly journals A Repressor Protein, PhaR, Regulates Polyhydroxyalkanoate (PHA) Synthesis via Its Direct Interaction with PHA

2002 ◽  
Vol 184 (14) ◽  
pp. 3992-4002 ◽  
Author(s):  
Akira Maehara ◽  
Seiichi Taguchi ◽  
Tatsuaki Nishiyama ◽  
Tsuneo Yamane ◽  
Yoshiharu Doi
Keyword(s):  
Paracoccus Denitrificans ◽  
Direct Interaction ◽  
Negative Regulator ◽  
Dna Complexes ◽  
Short Chain Length ◽  
Dnase I Footprinting ◽  
Associated Proteins ◽  
Direct Binding

ABSTRACT Phasins (PhaP) are predominantly polyhydroxyalkanoate (PHA) granule-associated proteins that positively affect PHA synthesis. Recently, we reported that the phaR gene, which is located downstream of phaP in Paracoccus denitrificans, codes for a negative regulator involved in PhaP expression. In this study, DNase I footprinting revealed that PhaR specifically binds to two regions located upstream of phaP and phaR, suggesting that PhaR plays a role in the regulation of phaP expression as well as autoregulation. Many TGC-rich sequences were found in upstream elements recognized by PhaR. PhaR in the crude lysate of recombinant Escherichia coli was able to rebind specifically to poly[(R)-3-hydroxybutyrate] [P(3HB)] granules. Furthermore, artificial P(3HB) granules and 3HB oligomers caused the dissociation of PhaR from PhaR-DNA complexes, but native PHA granules, which were covered with PhaP or other nonspecific proteins, did not cause the dissociation. These results suggest that PhaR is able to sense both the onset of PHA synthesis and the enlargement of the granules through direct binding to PHA. However, free PhaR is probably unable to sense the mature PHA granules which are already covered sufficiently with PhaP and/or other proteins. An in vitro expression experiment revealed that phaP expression was repressed by the addition of PhaR and was derepressed by the addition of P(3HB). Based on these findings, we present here a possible model accounting for the PhaR-mediated mechanism of PHA synthesis. Widespread distribution of PhaR homologs in short-chain-length PHA-producing bacteria suggests a common and important role of PhaR-mediated regulation of PHA synthesis.

scholarly journals Influence of Metal Ions on Microtubules as a Possible Mechanism of Pathogenesis of Alzheimer′s Disease

2018 ◽  
Vol 1 (3) ◽  
pp. e00050
Author(s):  
P.N. Shevtsov ◽  
E.F. Shevtsova ◽  
S.O. Bachurin
Keyword(s):  
Metal Ions ◽  
Inferior Olive ◽  
Postmortem Brain ◽  
Control Group ◽  
Destructive Effect ◽  
Aluminum Ions ◽  
Associated Proteins ◽  
The Brain

The article provides an overview of our own results of comparative study of influence of ions of iron, zinc and aluminium on the structure of microtubules from tubulin and microtubules associated proteins of rat brain with data on the structure of microtubules from tubulin and microtubules associated proteins from the brain of patients with Alzheimer′s disease (AD). A significant decrease in the amount of soluble tubulin was found in the postmortem brain of AD patients in comparison with the control group in the hippocampus, frontal cortex and substantia nigra, but not in the inferior olive. In vitro polymerization of tubulin and microtubules associated proteins from the brain of AD patients and electron micrographs of microtubules were obtained. The assembly of microtubules from brains of AD patients is disrupted, resulting in defective structures. On the other hand, the study of the influence of Al3+, Fe3+, Zn2+ on the microtubules from rat brains tubulin and microtubules associated proteins assembly and structure has shown that all studied metals are able to reduce the amount of microtubules and induce the assembly of anomal structures. According to the degree of the destructive effect on the microtubules and, accordingly, the possible significance in the pathogenesis of Alzheimer disease, metal ions can be arranged in the following sequence Al3+ > Zn2+ > Fe3+. Moreover, phosphorylation of tubulin and microtubules associated proteins in the presence of aluminum ions to the greatest extent reflects the phosphorylation of these proteins at AD. Comparison of data on the structure of microtubules after their assembly from brains of AD patients tubulin and microtubules associated proteins from brains of AD patients, and from the brain of rats, but in the presence of metal ions, confirm the conclusion about the possible role of the metals in the AD etiopathogenesis.

MARK2 Rescues Nogo-66-Induced Inhibition of Neurite Outgrowth via Regulating Microtubule-Associated Proteins in Neurons In Vitro

2016 ◽  
Vol 41 (11) ◽  
pp. 2958-2968
Author(s):  
Yu-Chao Zuo ◽  
Nan-Xiang Xiong ◽  
Jian-Ying Shen ◽  
Hua Yu ◽  
Yi-Zhi Huang ◽  
...  
Keyword(s):  
Neurite Outgrowth ◽  
Microtubule Associated Proteins ◽  
Associated Proteins

scholarly journals Cadherin-12 Regulates Neurite Outgrowth Through the PKA/Rac1/Cdc42 Pathway in Cortical Neurons

2021 ◽  
Vol 9 ◽  
Author(s):  
Beibei Guo ◽  
Mengwei Qi ◽  
Shuai Huang ◽  
Run Zhuo ◽  
Wenxue Zhang ◽  
...  
Keyword(s):  
Neurite Outgrowth ◽  
Cortical Neurons ◽  
Vital Role ◽  
Dependent Manner ◽  
Zebrafish Model ◽  
Axon Extension ◽  
The Brain

Cadherins play an important role in tissue homeostasis, as they are responsible for cell-cell adhesion during embryogenesis, tissue morphogenesis, and differentiation. In this study, we identified Cadherin-12 (CDH12), which encodes a type II classical cadherin, as a gene that promotes neurite outgrowth in an in vitro model of neurons with differentiated intrinsic growth ability. First, the effects of CDH12 on neurons were evaluated via RNA interference, and the results indicated that the knockdown of CDH12 expression restrained the axon extension of E18 neurons. The transcriptome profile of neurons with or without siCDH12 treatment revealed a set of pathways positively correlated with the effect of CDH12 on neurite outgrowth. We further revealed that CDH12 affected Rac1/Cdc42 phosphorylation in a PKA-dependent manner after testing using H-89 and 8-Bromo-cAMP sodium salt. Moreover, we investigated the expression of CDH12 in the brain, spinal cord, and dorsal root ganglia (DRG) during development using immunofluorescence staining. After that, we explored the effects of CDH12 on neurite outgrowth in vivo. A zebrafish model of CDH12 knockdown was established using the NgAgo-gDNA system, and the vital role of CDH12 in peripheral neurogenesis was determined. In summary, our study is the first to report the effect of CDH12 on axonal extension in vitro and in vivo, and we provide a preliminary explanation for this mechanism.

Analysis of the Mechanism of Microtubule Dynamic Instability Using a UV Microbeam to Sever Elongating Microtubules

1988 ◽  
Vol 46 ◽  
pp. 122-123
Author(s):  
R.A Walker ◽  
S. Inoue ◽  
E.D. Salmon
Keyword(s):  
Dynamic Instability ◽  
Microtubule Dynamic ◽  
Gtp Hydrolysis ◽  
Abrupt Transition ◽  
Microtubule Associated Proteins ◽  
Asymmetrical Structure ◽  
Associated Proteins

Microtubules polymerized in vitro from tubulin purified free of microtubule-associated proteins exhibit dynamic instability (1,2,3). Free microtubule ends exist in persistent phases of elongation or rapid shortening with infrequent, but, abrupt transitions between these phases. The abrupt transition from elongation to rapid shortening is termed catastrophe and the abrupt transition from rapid shortening to elongation is termed rescue. A microtubule is an asymmetrical structure. The plus end grows faster than the minus end. The frequency of catastrophe of the plus end is somewhat greater than the minus end, while the frequency of rescue of the plus end in much lower than for the minus end (4).The mechanism of catastrophe is controversial, but for both the plus and minus microtubule ends, catastrophe is thought to be dependent on GTP hydrolysis. Microtubule elongation occurs by the association of tubulin-GTP subunits to the growing end. Sometime after incorporation into an elongating microtubule end, the GTP is hydrolyzed to GDP, yielding a core of tubulin-GDP capped by tubulin-GTP (“GTP-cap”).

Effect of pH and inhibitors on beta-amyloid fibril assembly

1996 ◽  
Vol 54 ◽  
pp. 752-753
Author(s):  
Beverly E. Maleeff ◽  
Timothy K. Hart ◽  
Stephen J. Wood ◽  
Ronald Wetzel
Keyword(s):  
Amyloid Fibril ◽  
Peptide Fragment ◽  
Hydrophobic Peptides ◽  
Amyloid Fibril Formation ◽  
Effects Of Ph ◽  
Severity Of The Disease ◽  
Kinetics Of ◽  
The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

Molecular architecture and functions of the neuronal cytoskeleton

1990 ◽  
Vol 48 (3) ◽  
pp. 2-3
Author(s):  
Nobutaka Hirokawa
Keyword(s):  
Major Elements ◽  
Molecular Structures ◽  
Organelle Transport ◽  
Molecular Architecture ◽  
Neuronal Morphogenesis ◽  
Microtubule Associated Proteins ◽  
Associated Proteins ◽  
And Function ◽  
Small Clusters

In this symposium I will present our studies about the molecular architecture and function of the cytomatrix of the nerve cells. The nerve cell is a highly polarized cell composed of highly branched dendrites, cell body, and a single long axon along the direction of the impulse propagation. Each part of the neuron takes characteristic shapes for which the cytoskeleton provides the framework. The neuronal cytoskeletons play important roles on neuronal morphogenesis, organelle transport and the synaptic transmission. In the axon neurofilaments (NF) form dense arrays, while microtubules (MT) are arranged as small clusters among the NFs. On the other hand, MTs are distributed uniformly, whereas NFs tend to run solitarily or form small fascicles in the dendrites Quick freeze deep etch electron microscopy revealed various kinds of strands among MTs, NFs and membranous organelles (MO). These structures form major elements of the cytomatrix in the neuron. To investigate molecular nature and function of these filaments first we studied molecular structures of microtubule associated proteins (MAP1A, MAP1B, MAP2, MAP2C and tau), and microtubules reconstituted from MAPs and tubulin in vitro. These MAPs were all fibrous molecules with different length and formed arm like projections from the microtubule surface.

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