scholarly journals The Egalitarian binding partners Dynein light chain and Bicaudal-D act sequentially to link mRNA to the Dynein motor

Development ◽  
2019 ◽  
Vol 146 (15) ◽  
pp. dev176529 ◽  
Author(s):  
Chandler H. Goldman ◽  
Hannah Neiswender ◽  
Rajalakshmi Veeranan-Karmegam ◽  
Graydon B. Gonsalvez
Keyword(s):  
Light Chain ◽  
Dynein Light Chain ◽  
Binding Partners ◽  
Dynein Motor

scholarly journals Egalitarian binding partners, Dynein Light Chain and Bicaudal-D, act sequentially to link mRNA to the Dynein motor

2019 ◽  
Author(s):  
Chandler H. Goldman ◽  
Rajalakshmi Veeranan-Karmegam ◽  
Hannah Neiswender ◽  
Graydon B. Gonsalvez
Keyword(s):  
Light Chain ◽  
Rna Binding ◽  
Rna Binding Protein ◽  
Mrna Localization ◽  
Null Alleles ◽  
Dynein Light Chain ◽  
Binding Partners ◽  
Dynein Motor ◽  
Microtubule Motors

AbstractA widely conserved mechanism of polarity establishment is the localization of mRNA to specific cellular regions. While it is clear that many mRNAs are transported to their destinations along microtubule tracks, much less is known regarding the mechanism by which these mRNAs are linked to microtubule motors. The RNA binding protein Egalitarian (Egl) is necessary for localization of several mRNAs in Drosophila oocytes and embryos. In addition to binding RNA, Egl also interacts with Dynein light chain (Dlc) and Bicaudal-D (BicD). The role of Dlc and BicD in mRNA localization has remained elusive. Like Egl, both proteins are required for oocyte specification. Null alleles in these genes result in an oogenesis block. In this report, we used an innovative approach to overcome the oogenesis block. Our findings reveal that the primary function of Dlc is to promote Egl dimerization. Loss of dimerization compromises the ability of Egl to bind RNA. Consequently, Egl is not bound to cargo, and is not able to efficiently associate with BicD and the Dynein motor. Our results therefore identify the key molecular steps required for assembling a localization competent mRNP.

scholarly journals Functional interaction between dynein light chain and intermediate chain is required for mitotic spindle positioning

2011 ◽  
Vol 22 (15) ◽  
pp. 2690-2701 ◽  
Author(s):  
Melissa D. Stuchell-Brereton ◽  
Amanda Siglin ◽  
Jun Li ◽  
Jeffrey K. Moore ◽  
Shubbir Ahmed ◽  
...  
Keyword(s):  
Light Chain ◽  
Direct Evidence ◽  
Retrograde Transport ◽  
Cytoplasmic Dynein ◽  
Dynein Light Chain ◽  
Spindle Positioning ◽  
Dynein Motor ◽  
Intermediate Chains ◽  
Activator Complex

Cytoplasmic dynein is a large multisubunit complex involved in retrograde transport and the positioning of various organelles. Dynein light chain (LC) subunits are conserved across species; however, the molecular contribution of LCs to dynein function remains controversial. One model suggests that LCs act as cargo-binding scaffolds. Alternatively, LCs are proposed to stabilize the intermediate chains (ICs) of the dynein complex. To examine the role of LCs in dynein function, we used Saccharomyces cerevisiae, in which the sole function of dynein is to position the spindle during mitosis. We report that the LC8 homologue, Dyn2, localizes with the dynein complex at microtubule ends and interacts directly with the yeast IC, Pac11. We identify two Dyn2-binding sites in Pac11 that exert differential effects on Dyn2-binding and dynein function. Mutations disrupting Dyn2 elicit a partial loss-of-dynein phenotype and impair the recruitment of the dynein activator complex, dynactin. Together these results indicate that the dynein-based function of Dyn2 is via its interaction with the dynein IC and that this interaction is important for the interaction of dynein and dynactin. In addition, these data provide the first direct evidence that LC occupancy in the dynein motor complex is important for function.

scholarly journals Stage-specific Expression of Dynein Light Chain-1 and Its Interacting Kinase, p21-activated Kinase-1, in Rodent Testes: Implications in Spermiogenesis

2005 ◽  
Vol 53 (10) ◽  
pp. 1235-1243 ◽  
Author(s):  
Rui-An Wang ◽  
Ming Zhao ◽  
Marvin L. Meistrich ◽  
Rakesh Kumar
Keyword(s):  
Light Chain ◽  
Leydig Cells ◽  
Chromatin Condensation ◽  
Dynein Light Chain ◽  
Specific Expression ◽  
Regulatory Interactions ◽  
Dynein Motor ◽  
Complex Process ◽  
P21 Activated Kinase ◽  
Spermatogenic Epithelium

Mammalian spermatogenesis is a complex process involving regulatory interactions of many gene products. In this study, we found that dynein light chain-1 (DLC1), a component of the dynein motor complex, is highly expressed in mouse and rat testes. Immunohistochemically detectable levels of DLC1 are observed specifically in spermatids in steps 9–16 in distinct subcellular compartments: in steps 9–11, DLC1 is predominantly localized in the nucleus; in steps 12 and 13, it is found in both nucleus and cytoplasm; and in step 14–16, it is present exclusively in the cytoplasm. In addition, we found p21-activated kinase 1 (Pak1), a protein kinase that activates DLC1 by phosphorylating DLC1 at Serine 88, was also expressed during these stages of spermatogenesis. Pak1 was also expressed in Leydig cells, in preleptotene primary spermatocytes, and in round spermatids. The spermiogenic stage-specific expression of DLC1 suggests a role for DLC1 in chromatin condensation, spermatid shaping, and the final release of sperm from the spermatogenic epithelium. Further, Pak1 may also play a role in spermiogenesis by regulating DLC1 phosphorylation and, consequently, its function.

scholarly journals Novel function of a dynein light chain in actin assembly during clathrin-mediated endocytosis

2017 ◽  
Vol 216 (8) ◽  
pp. 2565-2580 ◽  
Author(s):  
Kristen B. Farrell ◽  
Seth McDonald ◽  
Andrew K. Lamb ◽  
Colette Worcester ◽  
Olve B. Peersen ◽  
...  
Keyword(s):  
Light Chain ◽  
Protein Family ◽  
Dependent Manner ◽  
Dynein Light Chain ◽  
Filamentous Actin ◽  
Capping Protein ◽  
Dynein Motor ◽  
Actin Capping Protein ◽  
Endocytic Machinery ◽  
Polyproline Motif

Clathrin- and actin-mediated endocytosis is essential in eukaryotic cells. In this study, we demonstrate that Tda2 is a novel protein of the endocytic machinery necessary for normal internalization of native cargo in yeast. Tda2 has not been classified in any protein family. Unexpectedly, solving the crystal structure of Tda2 revealed it belongs to the dynein light chain family. However, Tda2 works independently of the dynein motor complex and microtubules. Tda2 forms a tight complex with the polyproline motif–rich protein Aim21, which interacts physically with the SH3 domain of the Arp2/3 complex regulator Bbc1. The Tda2–Aim21 complex localizes to endocytic sites in a Bbc1- and filamentous actin–dependent manner. Importantly, the Tda2–Aim21 complex interacts directly with and facilitates the recruitment of actin-capping protein, revealing barbed-end filament capping at endocytic sites to be a regulated event. Thus, we have uncovered a new layer of regulation of the actin cytoskeleton by a member of a conserved protein family that has not been previously associated with a function in endocytosis.

scholarly journals Ebolavirus VP35 Interacts with the Cytoplasmic Dynein Light Chain 8

2009 ◽  
Vol 83 (13) ◽  
pp. 6952-6956 ◽  
Author(s):  
Toru Kubota ◽  
Mayumi Matsuoka ◽  
Tsung-Hsien Chang ◽  
Mike Bray ◽  
Steven Jones ◽  
...  
Keyword(s):  
Life Cycle ◽  
Light Chain ◽  
Viral Protein ◽  
Cytoplasmic Dynein ◽  
Type I ◽  
Dynein Light Chain ◽  
Yeast Two Hybrid ◽  
Binding Partners ◽  
Mapping Analysis ◽  
Two Hybrid

ABSTRACT The viral protein VP35 of ebolavirus (EBOV) is implicated to have diverse roles in the viral life cycle. We employed a yeast two-hybrid screen to search for VP35 binding partners and identified the cytoplasmic dynein light chain (DLC8) as a protein that interacts with VP35. Mapping analysis unraveled a consensus motif, SQTQT, within VP35 through which VP35 binds to DLC8. The disruption of DLC8 binding does not affect the ability of VP35 to inhibit type I IFN production. Given that VP35 from various EBOV species interacts with DLC8, this interaction may have a role in regulating the EBOV life cycle.

scholarly journals Dynein light chain 1 and a spindle-associated adaptor promote dynein asymmetry and spindle orientation

2012 ◽  
Vol 198 (6) ◽  
pp. 1039-1054 ◽  
Author(s):  
Anja K. Dunsch ◽  
Dean Hammond ◽  
Jennifer Lloyd ◽  
Lothar Schermelleh ◽  
Ulrike Gruneberg ◽  
...  
Keyword(s):  
Light Chain ◽  
Mitotic Spindle ◽  
Regulatory System ◽  
Cytoplasmic Dynein ◽  
Spindle Orientation ◽  
Growth Surface ◽  
Cell Cortex ◽  
Dynein Light Chain ◽  
Dynein Motor ◽  
Pulling Forces

The cytoplasmic dynein motor generates pulling forces to center and orient the mitotic spindle within the cell. During this positioning process, dynein oscillates from one pole of the cell cortex to the other but only accumulates at the pole farthest from the spindle. Here, we show that dynein light chain 1 (DYNLL1) is required for this asymmetric cortical localization of dynein and has a specific function defining spindle orientation. DYNLL1 interacted with a spindle-microtubule–associated adaptor formed by CHICA and HMMR via TQT motifs in CHICA. In cells depleted of CHICA or HMMR, the mitotic spindle failed to orient correctly in relation to the growth surface. Furthermore, CHICA TQT motif mutants localized to the mitotic spindle but failed to recruit DYNLL1 to spindle microtubules and did not correct the spindle orientation or dynein localization defects. These findings support a model where DYNLL1 and CHICA-HMMR form part of the regulatory system feeding back spindle position to dynein at the cell cortex.

scholarly journals Light chain 2 is a Tctex-type related axonemal dynein light chain that regulates directional ciliary motility in Trypanosoma brucei

2021 ◽  
Author(s):  
Subash Godar ◽  
James Oristian ◽  
Valerie Hinsch ◽  
Katherine Wentworth ◽  
Ethan Lopez ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Trypanosoma Brucei ◽  
Light Chain ◽  
Light Chains ◽  
Dynein Light Chain ◽  
Ciliary Beating ◽  
Ciliary Motility ◽  
Dynein Motor ◽  
Axonemal Dynein ◽  
Bending Wave

AbstractFlagellar motility is essential for the cell morphology, viability, and virulence of pathogenic kinetoplastids, including trypanosomes. Trypanosoma brucei flagella exhibit a bending wave that propagates from the flagellum’s tip to its base, rather than base-to-tip as in other eukaryotes. Thousands of dynein motor proteins coordinate their activity to drive ciliary bending wave propagation. Dynein- associated light and intermediate chains regulate the biophysical mechanisms of axonemal dynein. Tctex- type outer arm dynein light chain 2 (LC2) regulates flagellar bending wave propagation direction, amplitude, and frequency in Chlamydomonas reinhardtii. However, the role of Tctex-type light chains in regulating T. brucei motility is unknown. Here, we used a combination of bioinformatics, in-situ molecular tagging, and immunofluorescence microscopy to identify a Tctex-type light chain in the procyclic form of T. brucei (TbLC2). We knocked down TbLC2 expression using RNAi, rescued the knockdown with eGFP- tagged TbLC2, and quantified TbLC2’s effects on trypanosome cell biology and biophysics. We found that TbLC2 knockdown resulted in kinetoplast mislocalization and the formation of multiple cell clusters in cell culture. We also found that TbLC2 knockdown reduced the directional persistence of trypanosome cell swimming, induced an asymmetric ciliary bending waveform, modulated the bias between the base-to- tip and tip-to-base beating modes, and increased the beating frequency. Together, our findings are consistent with a model of TbLC2 as a down-regulator of axonemal dynein activity that stabilizes the forward tip-to-base beating ciliary waveform characteristic of trypanosome cells. Our work sheds light on axonemal dynein regulation mechanisms that contribute to pathogenic kinetoplastids’ unique tip-to-base ciliary beating nature and how those mechanisms underlie dynein-driven ciliary motility more generally.Author SummaryKinetoplastea is a class of ciliated protists that include parasitic trypanosomes, which cause severe disease in people and livestock in tropical regions across the globe. All trypanosomes, including Trypanosoma brucei, require a cilium to provide propulsive force for directional swimming motility, host immune evasion, and various aspects of their cell cycle. Thus, a functional cilium is essential for the virulence of the parasite.Trypanosome cilia exhibit a unique tip-to-base beating mechanism, different from the base-to-tip beating of most other eukaryotic cilia. Multiple ciliary proteins are involved in the complex biophysical and biochemical mechanisms that underly the trypanosome ciliary beating. These include dynein motor proteins that power the beat, dynein-related light chains that regulate the beat, and many other proteins in the nexin-dynein regulatory complex, in the radial spokes, and associated with the central pair of microtubules, for example.Here, we identify a Tctex-type dynein light chain in T. brucei that we named TbLC2 because it has sequence homology, structural similarity, and ciliary localization like LC2 homologs in other organisms. We demonstrate that TbLC2 has critical dynein regulatory functions, with implications on the unique aspects of trypanosome ciliary beating and cellular swimming motility. Our study represents an additional step toward understanding the functions of the trypanosome ciliary proteome, which could provide novel therapeutic targets against the unique aspects of trypanosome ciliary motility.

scholarly journals Dynein light chain-dependent dimerization of Egalitarian is essential for maintaining oocyte fate in Drosophila.

2021 ◽  
Author(s):  
Hannah Neiswender ◽  
Chandler H Goldman ◽  
Rajalakshmi Veeranan-Karmegam ◽  
Graydon B. Gonsalvez
Keyword(s):  
Light Chain ◽  
Leucine Zipper ◽  
Three Dimensional ◽  
Mrna Localization ◽  
Binding Activity ◽  
Dynein Light Chain ◽  
Dynein Motor ◽  
Mutant Phenotypes ◽  
Mrna Binding

Egalitarian (Egl) is an RNA adaptor for the Dynein motor and is thought to link numerous, perhaps hundreds, of mRNAs with Dynein. Dynein, in turn, is responsible for the transport and localization of these mRNAs. Studies have shown that efficient mRNA binding by Egl requires the protein to dimerize. We recently demonstrated that Dynein light chain (Dlc) is responsible for facilitating the dimerization of Egl. Mutations in Egl that fail to interact with Dlc do not dimerize, and as such, are defective for mRNA binding. Consequently, this mutant does not efficiently associate with BicaudalD (BicD), the factor responsible for linking the Egl/mRNA complex with Dynein. In this report, we tested whether artificially dimerizing this Dlc-binding mutant using a leucine zipper would restore mRNA binding and rescue mutant phenotypes in vivo. Interestingly, we found that although artificial dimerization of Egl restored BicD binding, it only partially restored mRNA binding. As a result, Egl-dependent phenotypes, such as oocyte specification and mRNA localization, were only partially rescued. We hypothesize that Dlc-mediated dimerization of Egl results in a three-dimensional conformation of the Egl dimer that is best suited for mRNA binding. Although the leucine zipper restores Egl dimerization, it likely does not enable Egl to assemble into the conformation required for maximal mRNA binding activity.

A motor independent requirement for Dynein light chain in C. elegans meiotic synapsis

Genetics ◽  
2021 ◽  
Author(s):  
Sara M Fielder ◽  
Tori Kent ◽  
Huiping Ling ◽  
Elizabeth J Gleason ◽  
William G Kelly
Keyword(s):  
Light Chain ◽  
Elevated Temperatures ◽  
Nuclear Periphery ◽  
High Growth ◽  
Binding Motif ◽  
Dynein Light Chain ◽  
C Elegans ◽  
Dynein Motor ◽  
Self Association ◽  
Meiotic Synapsis

Abstract The dynein motor complex is thought to aid in homolog pairing in many organisms by moving chromosomes within the nuclear periphery to promote and test homologous interactions. This precedes synaptonemal complex (SC) formation during homolog synapsis, which stabilizes homolog proximity during recombination. We observed that depletion of the dynein light chain (DLC-1) in Caenorhabditis elegans irreversibly prevents synapsis, causing an increase in off-chromatin formation of SC protein foci with increasing temperature. This requirement for DLC-1 is independent of its function in dynein motors, as SYP protein foci do not form with depletion of other dynein motor components. In contrast to normal SC-related structures, foci formed with DLC-1 depletion are resistant to dissolution with 1,6-hexanediol, similar to aggregates of SC proteins formed in high growth temperatures. Dynein light chains have been shown to act as hub proteins that interact with other proteins through a conserved binding motif. We identified a similar DLC-1 binding motif in the C. elegans SC protein SYP-2, and mutation of the putative motif causes meiosis defects that are exacerbated by elevated temperatures. We propose that DLC-1 acts as a pre-synapsis chaperone-like factor for SYP proteins to help regulate their self-association prior to the signals for SC assembly, a role that is revealed by its increased essentiality at elevated temperatures.

Sign in / Sign up

Export Citation Format

Share Document