Mycalolide B dissociates dynactin and abolishes retrograde axonal transport of dense-core vesicles

Cavolo, Samantha L.; Zhou, Chaoming; Ketcham, Stephanie A.; Suzuki, Matthew M.; Ukalovic, Kresimir; Silverman, Michael; Schroer, Trina A.; Levitan, Edwin S.

doi:10.1091/mbc.e14-11-1564

Cited by 15 publications

(9 citation statements)

References 36 publications

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“…With the collapse of both filopodia and lamellipodia following Myc B treatment, this suggests that both bundled and cross-linked networks of F-actin are disrupted via the actin severing activity of Myc B. Another target of Myc B is Dynactin, a complex containing actin and Actin-related protein-1 (Arp1) subunits involved in retrograde transport of neuronal vesicles 34 . Dynactin also participates in vesicular trafficking of matrix metalloproteinase-14 (MT1-MMP or MMP-14) 40 .…”

Section: Discussionmentioning

confidence: 99%

Effects of Modulating Actin Dynamics on HER2 Cancer Cell Motility and Metastasis

Nersesian

Williams

Newsted

et al. 2018

Sci Rep

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Amplification of HER2 leads to development of HER2-positive (HER2+) cancers with high rates of metastasis compared to other cancer subtypes. The goal of this study was to probe the vulnerability of HER2+ cancer cells to a filamentous actin (F-actin) severing and capping toxin. The growth and viability of human HER2+ breast cancer (HCC1954) and ovarian cancer (SKOV3) cell lines were significantly impaired upon treatment with the marine macrolide mycalolide B (Myc B) at doses above 100 nanomolar. Further testing of Myc B in combination with the antibody-drug conjugate Trastuzumab-emtansine (T-DM1) led to improved killing of SKOV3 cells compared to either treatment alone. At sub-lethal doses, treatment of HER2+ cancer cells with Myc B resulted in rapid loss of leading edge protrusions and formation of aggresomes containing F-actin and the actin regulatory protein Cortactin. This correlated with robust inhibition of HER2+ cancer cell motility and invasion with Myc B treatment. In SKOV3 tumor xenograft assays, intratumoral injections of Myc B impaired HER2+ tumor growth and metastasis, with maximal effects observed in combination with systemic delivery of Trastuzumab. Metastasis of SKOV3 cells to the lungs following tail vein injection was also reduced by Myc B. Together, these findings provide rationale for targeting F-actin in combination with existing therapies for HER2+ cancers to reduce metastasis.

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Section: Discussionmentioning

confidence: 99%

Effects of Modulating Actin Dynamics on HER2 Cancer Cell Motility and Metastasis

Nersesian

Williams

Newsted

et al. 2018

Sci Rep

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“…The resulting velocity can be intermediate anywhere between the fast and slow limits, depending on the ratio and relative activity of fast and slow motor species on each cargo (27,38). We tested for the first possibility and released load with mycalolide B, which disrupts the dynactin complex and inhibits actin polymerization (28,29). We measured increased anterograde particle velocities during egress.…”

Section: Discussionmentioning

confidence: 99%

Dual-Color Herpesvirus Capsids Discriminate Inoculum from Progeny and Reveal Axonal Transport Dynamics

Scherer

Yaffe

Vershinin

et al. 2016

J Virol

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Alphaherpesviruses such as herpes simplex virus and pseudorabies virus (PRV) are neuroinvasive double-stranded DNA (dsDNA) viruses that establish lifelong latency in peripheral nervous system (PNS) neurons of their native hosts. Following reactivation, infection can spread back to the initial mucosal site of infection or, in rare cases, to the central nervous system, with usually serious outcomes. During entry and egress, viral capsids depend on microtubule-based molecular motors for efficient and fast transport. In axons of PNS neurons, cytoplasmic dynein provides force for retrograde movements toward the soma, and kinesins move cargo in the opposite, anterograde direction. The dynamic properties of virus particles in cells can be imaged by fluorescent protein fusions to the small capsid protein VP26, which are incorporated into capsids. However, single-color fluorescent protein tags fail to distinguish the virus inoculum from progeny. Therefore, we established a dual-color system by growing a recombinant PRV expressing a red fluorescent VP26 fusion (PRV180) on a stable cell line expressing a green VP26 fusion (PK15-mNG-VP26). The resulting dual-color virus preparation (PRV180G) contains capsids tagged with both red and green fluorescent proteins, and 97% of particles contain detectable levels of mNeonGreen (mNG)-tagged VP26. After replication in neuronal cells, all PRV180G progeny exclusively contain monomeric red fluorescent protein (mRFP)-VP26-tagged capsids. We used PRV180G for an analysis of axonal capsid transport dynamics in PNS neurons. Fast dual-color total internal reflection fluorescence (TIRF) microscopy, single-particle tracking, and motility analyses reveal robust, bidirectional capsid motility mediated by cytoplasmic dynein and kinesin during entry, whereas egressing progeny particles are transported exclusively by kinesins. IMPORTANCE Alphaherpesviruses are neuroinvasive viruses that infect the peripheral nervous system (PNS) of infected hosts as an integral part of their life cycle. Establishment of a quiescent or latent infection in PNS neurons is a hallmark of most alphaherpesviruses.Spread of infection to the central nervous system is surprisingly rare in natural hosts but can be fatal. Pseudorabies virus (PRV) is a broad-host-range swine alphaherpesvirus that enters neuronal cells and utilizes intracellular transport processes to establish infection and to spread between cells. By using a virus preparation with fluorescent viral capsids that change color depending on the stage of the infectious cycle, we find that during entry, axons of PNS neurons support robust, bidirectional capsid motility, similar to cellular cargo, toward the cell body. In contrast, progeny particles appear to be transported unidirectionally by kinesin motors toward distal egress sites.A lphaherpesviruses (e.g., human herpes simplex virus [HSV] and swine pseudorabies virus [PRV]) are neuroinvasive double-stranded DNA (dsDNA) viruses with virions consisting of a nucleocapsid surrounded by a proteinaceous tegu...

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“…Studies of endocrine and exocrine cells with 300–1000 nm LDCVs have often implicated F-actin (and sometimes myosin) in release, because it apparently takes work to move these large vesicles and extrude their contents. In contrast, experiments on synaptic neuropeptide vesicles with cytochalasin and mycalolide B (an F-actin/dynactin disruptor) showed that F-actin does not affect LDCV mobilization, anterograde transport, synaptic capture or evoked synaptic neuropeptide release (Shakiryanova et al, 2005 ; Cavolo et al, 2015 , 2016 ).…”

Section: State Of Art On High Molecular Weight Neurotransmitter Localmentioning

confidence: 99%

Costorage of High Molecular Weight Neurotransmitters in Large Dense Core Vesicles of Mammalian Neurons

Merighi

2018

Front. Cell. Neurosci.

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It is today widely accepted that several types of high molecular weight (MW) neurotransmitters produced by neurons are synthesized at the cell body, selectively stored within large dense core vesicles (LDCVs) and anterogradely transported to terminals where they elicit their biological role(s). Among these molecules there are neuropeptides and neurotrophic factors, the main focus of this perspective article. I here first provide a brief resume of the state of art on neuronal secretion, with primary emphasis on the molecular composition and mechanism(s) of filling and release of LDCVs. Then, I discuss the perspectives and future directions of research in the field as regarding the synthesis and storage of multiple high MW transmitters in LDCVs and the possibility that a selective sorting of LDCVs occurs along different neuronal processes and/or their branches. I also consider the ongoing discussion that diverse types of neurons may contain LDCVs with different sets of integral proteins or dial in a different fashion with LDCVs containing the same cargo. In addition, I provide original data on the size of LDCVs in rat dorsal root ganglion neurons and their central terminals in the spinal cord after immunogold labeling for calcitonin gene-related peptide (CGRP), neuropeptide K, substance P, neurokinin A or somatostatin. These data corroborate the idea that, similarly to endocrine cells, LDCVs undergo a process of maturation which involves a homotypic fusion followed by a reduction in size and condensation of cargo. They also give support to the conjecture that release at terminals occurs by cavicapture, a process of partial fusion of the vesicle with the axolemma, accompanied by depletion of cargo and diminution of size.

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Mycalolide B dissociates dynactin and abolishes retrograde axonal transport of dense-core vesicles

Cited by 15 publications

References 36 publications

Effects of Modulating Actin Dynamics on HER2 Cancer Cell Motility and Metastasis

Effects of Modulating Actin Dynamics on HER2 Cancer Cell Motility and Metastasis

Dual-Color Herpesvirus Capsids Discriminate Inoculum from Progeny and Reveal Axonal Transport Dynamics

Costorage of High Molecular Weight Neurotransmitters in Large Dense Core Vesicles of Mammalian Neurons

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