scholarly journals Two single-headed myosin V motors bound to a tetrameric adapter protein form a processive complex

2011 ◽  
Vol 195 (4) ◽  
pp. 631-641 ◽  
Author(s):  
Elena B. Krementsova ◽  
Alex R. Hodges ◽  
Carol S. Bookwalter ◽  
Thomas E. Sladewski ◽  
Mirko Travaglia ◽  
...  
Keyword(s):  
Messenger Rna ◽  
Adapter Protein ◽  
Myosin V ◽  
Hand Motion ◽  
Mrna Binding Protein ◽  
Myosin Va ◽  
Α Helix ◽  
Mrna Binding ◽  
Cargo Binding

Myo4p, one of two class V myosins in budding yeast, continuously transports messenger RNA (mRNA) cargo in the cell but is nonprocessive when characterized in vitro. The adapter protein She3p tightly binds to the Myo4p rod, forming a single-headed motor complex. In this paper, we show that two Myo4p–She3p motors are recruited by the tetrameric mRNA-binding protein She2p to form a processive double-headed complex. The binding site for She3p was mapped to a single α helix that protrudes at right angles from She2p. Processive runs of several micrometers on yeast actin–tropomyosin filaments were observed only in the presence of She2p, and, thus, motor activity is regulated by cargo binding. While moving processively, each head steps ∼72 nm in a hand-over-hand motion. Coupling two high-duty cycle monomeric motors via a common cargo-binding adapter protein creates a complex with transport properties comparable with a single dimeric processive motor such as vertebrate myosin Va.

The roles of Insulin-like growth factor-II messenger RNA (mRNA)-binding protein-3 (IMP-3) in melanoma progression

2013 ◽  
Vol 69 (2) ◽  
pp. e20-e21
Author(s):  
Chia-Yu Chu ◽  
Yi-Shuan Sheen ◽  
Kuanyin K. Lin ◽  
Meng-Chen Hsieh ◽  
Hsien-Ching Chiu ◽  
...  
Keyword(s):  
Growth Factor ◽  
Messenger Rna ◽  
Binding Protein ◽  
Insulin Like Growth Factor ◽  
Melanoma Progression ◽  
Factor Ii ◽  
Mrna Binding Protein ◽  
Mrna Binding

scholarly journals An Interaction between Two RNA Binding Proteins, Nab2 and Pub1, Links mRNA Processing/Export and mRNA Stability

2007 ◽  
Vol 27 (18) ◽  
pp. 6569-6579 ◽  
Author(s):  
Luciano H. Apponi ◽  
Seth M. Kelly ◽  
Michelle T. Harreman ◽  
Alexander N. Lehner ◽  
Anita H. Corbett ◽  
...  
Keyword(s):  
Mrna Stability ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Tail Length ◽  
Functional Link ◽  
Mrna Binding Protein ◽  
Mrna Binding

ABSTRACT mRNA stability is modulated by elements in the mRNA transcript and their cognate RNA binding proteins. Poly(U) binding protein 1 (Pub1) is a cytoplasmic Saccharomyces cerevisiae mRNA binding protein that stabilizes transcripts containing AU-rich elements (AREs) or stabilizer elements (STEs). In a yeast two-hybrid screen, we identified nuclear poly(A) binding protein 2 (Nab2) as being a Pub1-interacting protein. Nab2 is an essential nucleocytoplasmic shuttling mRNA binding protein that regulates poly(A) tail length and mRNA export. The interaction between Pub1 and Nab2 was confirmed by copurification and in vitro binding assays. The interaction is mediated by the Nab2 zinc finger domain. Analysis of the functional link between these proteins reveals that Nab2, like Pub1, can modulate the stability of specific mRNA transcripts. The half-life of the RPS16B transcript, an ARE-like sequence-containing Pub1 target, is decreased in both nab2-1 and nab2-67 mutants. In contrast, GCN4, an STE-containing Pub1 target, is not affected. Similar results were obtained for other ARE- and STE-containing Pub1 target transcripts. Further analysis reveals that the ARE-like sequence is necessary for Nab2-mediated transcript stabilization. These results suggest that Nab2 functions together with Pub1 to modulate mRNA stability and strengthen a model where nuclear events are coupled to the control of mRNA turnover in the cytoplasm.

scholarly journals Neuron-Specific IMP2 Overexpression by Synapsin Promoter-Driven AAV9: A Tool to Study Its Role in Axon Regeneration

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2654
Author(s):  
Sarah Blizard ◽  
Danielle Park ◽  
Natalie O’Toole ◽  
Sheeva Norooz ◽  
Martin Dela Torre ◽  
...  
Keyword(s):  
Viral Vectors ◽  
Axon Regeneration ◽  
Viral Vector ◽  
Binding Protein ◽  
Factor Ii ◽  
Mrna Binding Protein ◽  
Specific Mrnas ◽  
Mrna Binding

Insulin-like growth factor II mRNA-binding protein (IMP) 2 is one of the three homologues (IMP1-3) that belong to a conserved family of mRNA-binding proteins. Its alternative splice product is aberrantly expressed in human hepatocellular carcinoma, and it is therefore identified as HCC. Previous works have indicated that IMP1/ZBP1 (zipcode binding protein) is critical in axon guidance and regeneration by regulating localization and translation of specific mRNAs. However, the role of IMP2 in the nervous system is largely unknown. We used the synapsin promoter-driven adeno-associated viral (AAV) 9 constructs for transgene expression both in vitro and in vivo. These viral vectors have proven to be effective to transduce the neuron-specific overexpression of IMP2 and HCC. Applying this viral vector in the injury-conditioned dorsal root ganglion (DRG) culture demonstrates that overexpression of IMP2 significantly inhibits axons regenerating from the neurons, whereas overexpression of HCC barely interrupts the process. Quantitative analysis of binding affinities of IMPs to β-actin mRNA reveals that it is closely associated with their roles in axon regeneration. Although IMPs share significant structural homology, the distinctive functions imply their different ability to localize specific mRNAs and to regulate the axonal translation.

scholarly journals High-Throughput Fluorescence Anisotropy Screen for Inhibitors of the Oncogenic mRNA Binding Protein, IMP-1

2013 ◽  
Vol 19 (3) ◽  
pp. 427-436 ◽  
Author(s):  
Lily Mahapatra ◽  
Chengjian Mao ◽  
Neal Andruska ◽  
Chen Zhang ◽  
David J. Shapiro
Keyword(s):  
Small Molecule ◽  
High Throughput ◽  
Fluorescence Anisotropy ◽  
Messenger Rnas ◽  
High Throughput Screen ◽  
Alternative Approach ◽  
Mrna Binding Protein ◽  
Elevated Expression ◽  
Mrna Binding

Cancer cell proliferation is regulated by oncogenes, such as c-Myc. An alternative approach to directly targeting individual oncogenes is to target IMP-1, an oncofetal protein that binds to and stabilizes messenger RNAs (mRNAs), leading to elevated expression of c-Myc and other oncogenes. Expression of IMP-1 is tightly correlated with a poor prognosis and reduced survival in ovarian, lung, and colon cancer. Small-molecule inhibitors of IMP-1 have not been reported. We established a fluorescence anisotropy/polarization microplate assay (FAMA) for analyzing binding of IMP-1 to a fluorescein-labeled 93 nucleotide c-Myc mRNA target (flMyc), developed the assay as a highly robust (Z′ factor = 0.60) FAMA-based high-throughput screen for inhibitors of binding of IMP-1 to flMyc, and carried out a successful pilot screen of 17,600 small molecules. Our studies support rapidly filtering out toxic nonspecific inhibitors using an early cell-based assay in control cells lacking the target protein. The physiologic importance of verified hits from the in vitro high-throughput screen was demonstrated by identification of the first small-molecule IMP-1 inhibitor, a lead compound that selectively inhibits proliferation of IMP-1–positive cancer cells with very little or no effect on proliferation of IMP-1–negative cells.

Myosin Va is involved in transport of the mRNA-binding protein from the nucleus to the cytoplasm in neurons

2010 ◽  
Vol 68 ◽  
pp. e353-e354
Author(s):  
Fumitake Sugiyama ◽  
Yoshiko Takagishi ◽  
Xiao-yang Sun ◽  
Yoshiharu Murata
Keyword(s):  
Binding Protein ◽  
Mrna Binding Protein ◽  
Myosin Va ◽  
Mrna Binding

scholarly journals SYNCRIP facilitates porcine parvovirus viral DNA replication through the alternative splicing of NS1 mRNA to promote NS2 mRNA formation

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Songbiao Chen ◽  
Bichen Miao ◽  
Nannan Chen ◽  
Caiyi Chen ◽  
Ting Shao ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Porcine Parvovirus ◽  
Nonstructural Proteins ◽  
Protein Levels ◽  
Mrna Binding Protein ◽  
Infected Cells ◽  
Mrna Binding ◽  
Terminal Site

AbstractPorcine Parvovirus (PPV), a pathogen causing porcine reproductive disorders, encodes two capsid proteins (VP1 and VP2) and three nonstructural proteins (NS1, NS2 and SAT) in infected cells. The PPV NS2 mRNA is from NS1 mRNA after alternative splicing, yet the corresponding mechanism is unclear. In this study, we identified a PPV NS1 mRNA binding protein SYNCRIP, which belongs to the hnRNP family and has been identified to be involved in host pre-mRNA splicing by RNA-pulldown and mass spectrometry approaches. SYNCRIP was found to be significantly up-regulated by PPV infection in vivo and in vitro. We confirmed that it directly interacts with PPV NS1 mRNA and is co-localized at the cytoplasm in PPV-infected cells. Overexpression of SYNCRIP significantly reduced the NS1 mRNA and protein levels, whereas deletion of SYNCRIP significantly reduced NS2 mRNA and protein levels and the ratio of NS2 to NS1, and further impaired replication of the PPV. Furthermore, we found that SYNCRIP was able to bind the 3′-terminal site of NS1 mRNA to promote the cleavage of NS1 mRNA into NS2 mRNA. Taken together, the results presented here demonstrate that SYNCRIP is a critical molecule in the alternative splicing process of PPV mRNA, while revealing a novel function for this protein and providing a potential target of antiviral intervention for the control of porcine parvovirus disease.

scholarly journals Recruitment of Two Dyneins to an mRNA-Dependent Bicaudal D Transport Complex

2018 ◽  
Author(s):  
Thomas E. Sladewski ◽  
Neil Billington ◽  
M. Yusuf Ali ◽  
Carol S. Bookwalter ◽  
Hailong Lu ◽  
...  
Keyword(s):  
Single Molecule ◽  
Optimal Transport ◽  
Adaptor Proteins ◽  
Full Length ◽  
Messenger Ribonucleoprotein ◽  
Mrna Binding Protein ◽  
Run Lengths ◽  
Transport Complex ◽  
Mrna Binding

AbstractWe investigated the role of binding partners of full-length Drosophila Bicaudal D (BicD) in the activation of dynein-dynactin motility for mRNA transport on microtubules. In single-molecule assays, full-length BicD robustly activated dynein-dynactin only when both the mRNA binding protein Egalitarian (Egl), and K10 mRNA cargo were present. Electron microscopy showed that both Egl and mRNA were needed to disrupt an auto-inhibited, looped BicD conformation that sterically prevents dynein-dynactin binding. In vitro reconstituted messenger ribonucleoprotein (mRNP) complexes with two Egl molecules showed faster speeds and longer run lengths than mRNPs with one Egl, suggesting that cargo binding enhances dynein recruitment. Labeled dynein showed that BicD can recruit two dimeric dyneins to the mRNP, resulting in faster speeds and longer run lengths than with one dynein. The fully reconstituted mRNP provides a model for understanding how adaptor proteins and cargo cooperate to confer optimal transport properties to a dynein-driven transport complex.

scholarly journals Essential Features of the Class V Myosin from Budding Yeast for ASH1 mRNA Transport

2009 ◽  
Vol 20 (14) ◽  
pp. 3414-3421 ◽  
Author(s):  
Carol S. Bookwalter ◽  
Matthew Lord ◽  
Kathleen M. Trybus
Keyword(s):  
Daughter Cell ◽  
Leucine Zipper ◽  
Budding Yeast ◽  
Binding Protein ◽  
Adapter Protein ◽  
Class V ◽  
Mrna Binding Protein ◽  
Ash1 Mrna ◽  
Mrna Binding ◽  
Zip Code

Myo4p, a single-headed and nonprocessive class V myosin in budding yeast, transports >20 different mRNAs asymmetrically to the bud. Here, we determine the features of the Myo4p motor that are necessary for correct localization of ASH1 mRNA to the daughter cell, a process that also requires the adapter protein She3p and the dimeric mRNA-binding protein She2p. The rod region of Myo4p, but not the globular tail, is essential for correct localization of ASH1 mRNA, confirming that the rod contains the primary binding site for She3p. The requirement for both the rod region and She3p can be bypassed by directly coupling the mRNA-binding protein She2p to Myo4p. ASH1 mRNA was also correctly localized when one motor was bound per dimeric She2p, or when two motors were joined together by a leucine zipper. Because multiple mRNAs are cotransported to the bud, it is likely that this process involves multiple motor transport regardless of the number of motors per zip code. Our results show that the most important feature for correct localization is the retention of coupling between all the members of the complex (Myo4p–She3p–She2p–ASH1 mRNA), which is aided by She3p being a tightly bound subunit of Myo4p.

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