Changes in membrane trafficking and actin dynamics during axon formation in cultured hippocampal neurons

Bradke, Frank; Dotti, Carlos G.

doi:10.1002/(sici)1097-0029(20000101)48:1<3::aid-jemt2>3.0.co;2-o

Cited by 26 publications

(12 citation statements)

References 95 publications

(95 reference statements)

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“…Proper neurite outgrowth and subsequent axon formation depend on a dynamic balance of F-actin at the peripheral area and microtubules at the central domain of the filopodia (Bridgman and Dailey, 1989;Baas et al, 1989). Although the exact mechanism remains undetermined, one widely-accepted hypothesis suggests that the instability of F-actin favors the protrusion and formation of axons (Bradke and Dotti, 2000). At the very early stages of neuron development, the filopodial dynamics are similar among all of the neurites in which F-actin restricts further protrusion of microtubules (Bradke and Dotti, 2000).…”

Section: Discussionmentioning

confidence: 99%

“…Although the exact mechanism remains undetermined, one widely-accepted hypothesis suggests that the instability of F-actin favors the protrusion and formation of axons (Bradke and Dotti, 2000). At the very early stages of neuron development, the filopodial dynamics are similar among all of the neurites in which F-actin restricts further protrusion of microtubules (Bradke and Dotti, 2000). Later, F-actin becomes less stable in one of the neurites, allowing the protrusion of microtubules and formation of axons (Bradke and Dotti, 1999).…”

Section: Discussionmentioning

confidence: 99%

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Phosphorylation of Ezrin/Radixin/Moesin Proteins by LRRK2 Promotes the Rearrangement of Actin Cytoskeleton in Neuronal Morphogenesis

Parisiadou¹,

et al. 2009

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Leucine-rich repeat kinase 2 (LRRK2) functions as a putative protein kinase of ezrin, radixin, and moesin (ERM) family proteins. A Parkinson's disease-related G2019S substitution in the kinase domain of LRRK2 further enhances the phosphorylation of ERM proteins. The phosphorylated ERM (pERM) proteins are restricted to the filopodia of growing neurites in which they tether filamentous actin (F-actin) to the cytoplasmic membrane and regulate the dynamics of filopodia protrusion. Here, we show that, in cultured neurons derived from LRRK2 G2019S transgenic mice, the number of pERM-positive and F-actin-enriched filopodia was significantly increased, and this correlates with the retardation of neurite outgrowth. Conversely, deletion of LRRK2, which lowered the pERM and F-actin contents in filopodia, promoted neurite outgrowth. Furthermore, inhibition of ERM phosphorylation or actin polymerization rescued the G2019S-dependent neuronal growth defects. These data support a model in which the G2019S mutation of LRRK2 causes a gain-offunction effect that perturbs the homeostasis of pERM and F-actin in sprouting neurites critical for neuronal morphogenesis.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Phosphorylation of Ezrin/Radixin/Moesin Proteins by LRRK2 Promotes the Rearrangement of Actin Cytoskeleton in Neuronal Morphogenesis

Parisiadou¹,

et al. 2009

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“…Ultimately, these signaling cascades converge at the level of the cytoskeleton to generate localized structural rearrangement through the mechanism of symmetry breaking. During the establishment of neuronal polarity, symmetry breaking events occur first at the Stage I-II transition, triggering minor process extension from the spherical neuronal cell body, and second, at the Stage II-III transition, allowing one process to lengthen significantly and establish an axonal phenotype (Bradke and Dotti, 2000a,b; Da Silva and Dotti, 2002). Our data suggest that myosin II may be responsible for maintaining the neuronal sphere in newly postmitotic neurons, generating contractile forces against cortical actin to produce a barrier against cytoskeletal changes that trigger minor process outgrowth.…”

Section: Discussionmentioning

confidence: 99%

“…For hippocampal and forebrain neurons, polarity arises in vitro through a well-characterized sequence of morphological changes (Craig and Banker, 1994; Bradke and Dotti, 2000a, b; Heidemann et al, 2003; Dehmelt and Halpain, 2004; Arimura and Kaibuchi, 2007). Following attachment to a permissive substrate, these neurons extend broad actin-rich lamellipodia and filopodia (Stage I) which then segment and condense into multiple undifferentiated neurites, termed minor processes (Stage II).…”

mentioning

confidence: 99%

Myosin‐II negatively regulates minor process extension and the temporal development of neuronal polarity

Kollins

Bridgman

et al. 2009

Developmental Neurobiology

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The earliest stage in the development of neuronal polarity is characterized by extension of undifferentiated "minor processes" (MPs), which subsequently differentiate into the axon and dendrites. We investigated the role of the myosin II motor protein in MP extension using forebrain and hippocampal neuron cultures. Chronic treatment of neurons with the myosin II ATPase inhibitor blebbistatin increased MP length, which was also seen in myosin IIB knockouts. Through live-cell imaging we demonstrate that myosin II inhibition triggers rapid minor process extension to a maximum length range. Myosin II activity is determined by phosphorylation of its regulatory light chains (rMLC), mediated by myosin light chain kinase (MLCK) or RhoA-kinase (ROCK). Pharmacological inhibition of MLCK or ROCK increased MP length moderately, with combined inhibition of these kinases resulting in an additive increase in MP length similar to the effect of direct inhibition of myosin II. Selective inhibition of RhoA signaling upstream of ROCK, with cell-permeable C3 transferase, increased both the length and number of MPs. To determine whether myosin II affected development of neuronal polarity, MP differentiation was examined in cultures treated with direct or indirect myosin II inhibitors. Significantly, inhibition of myosin II, MLCK, or ROCK accelerated the development of neuronal polarity. Increased myosin II activity, through constitutively active MLCK or RhoA, decreased both the length and number of MPs and, consequently, delayed or abolished the development of neuronal polarity. Together, these data indicate that myosin II negatively regulates MP extension, and the developmental time course for axonogenesis.Keywords myosin II; myosin light chain kinase; Rho-kinase; minor process; polarity; neuronal development Establishment of appropriate functional connectivity in the nervous system requires regulated development of axons and dendrites, generating and maintaining neuronal polarity. For hippocampal and forebrain neurons, polarity arises in vitro through a wellcharacterized sequence of morphological changes (Craig and Banker, 1994; Bradke and Dotti, 2000a, b;Heidemann et al., 2003;Dehmelt and Halpain, 2004;Arimura and Kaibuchi, 2007). Following attachment to a permissive substrate, these neurons extend broad actin-rich lamellipodia and filopodia (Stage I) which then segment and condense into multiple NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript undifferentiated neurites, termed minor processes (Stage II). Through asymmetric growth, one minor process becomes significantly longer than the others, eventually attaining an axonal phenotype (StageIII), while the remaining minor processes subsequently differentiate into dendrites (Stage IV). Although the stereotyped sequence of morphogenesis is known, the cellular and molecular mechanisms governing the establishment of neuronal polarity are not fully understood.Myosin II is a mechanoenzyme that generates cellular contractile forces through interaction w...

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“…Among these two clusters of 272 genes, several actin and tubulin isoforms were identified in these clusters, including betaand gamma-actin, actin-1, and actin-3, as well as several forms of alpha-and beta-tubulin, consistent with the notion that cellular differentiation is associated with the dynamic production of cytoskeletal and structural proteins (37). Interestingly, genes encoding the CCT chaperonin-containing family are prominently expressed in the same cluster (38).…”

Section: Genetic Events During Neonatal and Early Postnatal Developmentmentioning

confidence: 99%

Genome-wide gene expression profiles of the developing mouse hippocampus

Mody

Cao

Cui

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

191

172

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We have analyzed the developmental molecular programs of the mouse hippocampus, a cortical structure critical for learning and memory, by means of large-scale DNA microarray techniques. Of 11,000 genes and expressed sequence tags examined, 1,926 showed dynamic changes during hippocampal development from embryonic day 16 to postnatal day 30. Gene-cluster analysis was used to group these genes into 16 distinct clusters with striking patterns that appear to correlate with major developmental hallmarks and cellular events. These include genes involved in neuronal proliferation, differentiation, and synapse formation. A complete list of the transcriptional changes has been compiled into a comprehensive gene profile database (http:͞͞BrainGenomics. Princeton.edu), which should prove valuable in advancing our understanding of the molecular and genetic programs underlying both the development and the functions of the mammalian brain.

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Changes in membrane trafficking and actin dynamics during axon formation in cultured hippocampal neurons

Cited by 26 publications

References 95 publications

Phosphorylation of Ezrin/Radixin/Moesin Proteins by LRRK2 Promotes the Rearrangement of Actin Cytoskeleton in Neuronal Morphogenesis

Phosphorylation of Ezrin/Radixin/Moesin Proteins by LRRK2 Promotes the Rearrangement of Actin Cytoskeleton in Neuronal Morphogenesis

Myosin‐II negatively regulates minor process extension and the temporal development of neuronal polarity

Genome-wide gene expression profiles of the developing mouse hippocampus

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