Interactions of Cytoplasmic Dynein Light Chains Tctex-1 and LC8 with the Intermediate Chain IC74

Makokha, Moses; Hare, Michael; Li, Mingang; Hays, Thomas S.; Barbar, Elisar

doi:10.1021/bi011970h

Cited by 102 publications

(140 citation statements)

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“…Previous work revealed that LC8 binds to DIC 29,30 , but the binding partner of Arl3 is unknown. To examine whether Arl3 binds either dynein, dynactin or LC8, we performed glutathione S-transferase (GST) pull-down assays using Arl3-conjugated beads.…”

Section: Resultsmentioning

confidence: 99%

Arl3 and LC8 regulate dissociation of dynactin from dynein

et al. 2014

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Cytoplasmic dynein acts as a motor for the intracellular retrograde motility of vesicles and organelles along microtubules. However, the regulatory mechanism underlying release of dynactin bound cargoes from dynein motor remains largely unknown. Here we report that ADP-ribosylation factor-like 3 (Arl3) and dynein light chain LC8 induce dissociation of dynactin from dynein. Immunoprecipitation and microtubule pull-down assays revealed that Arl3(Q71L) and LC8 facilitated detachment of dynactin from dynein. We also demonstrated Arl3(Q71L) or LC8-mediated dynactin release from a dynein-dynactin complex through trace experiments using quantum dot (Qdot)-conjugated proteins. Furthermore, we disclosed interactions of Arl3 and LC8 with dynactin and dynein, respectively, by live-cell imaging. Finally, knockdown (KD) of Arl3 and LC8 by siRNA induced abnormal localizations of dynein, dynactin and related organelles. Our findings uncovered the surprising functional relevance of GTP-bound Arl3 and LC8 for the unloading regulation of dynactin-bound cargo from dynein motor.

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Section: Resultsmentioning

confidence: 99%

Arl3 and LC8 regulate dissociation of dynactin from dynein

et al. 2014

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“…There does not seem to be a family member in Saccharomyces cerevisiae. There are also other DLC families that bind to DIC, including Tctex-1/LC14, Tctex-2/LC2, LC6, and LC8/PIN (Bowman et al, 1999;King, 2000;Makokha et al, 2002). Of these other DLCs that bind to the DIC, Tctex-1 and LC8 have been shown to function as motor receptors to link cargo to the motor machinery (Almenar-Queralt and Goldstein, 2001).…”

Section: Resultsmentioning

confidence: 99%

“…Of these other DLCs that bind to the DIC, Tctex-1 and LC8 have been shown to function as motor receptors to link cargo to the motor machinery (Almenar-Queralt and Goldstein, 2001). Although Tctex-1 and LC8 share limited sequence identity, both bind a number of unrelated cargo in a similar manner (Mok et al, 2001;Makokha et al, 2002). Similarly, these DLCs are only 8 and 14% identical to mLC7-1, respectively.…”

Section: Molecular Biology Of the Cell 4486mentioning

confidence: 99%

A Novel Transforming Growth Factor-β Receptor-interacting Protein That Is Also a Light Chain of the Motor Protein Dynein

Tang¹,

Staub²,

Gao

et al. 2002

MBoC

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The phosphorylated, activated cytoplasmic domains of the transforming growth factor-␤ (TGF␤) receptors were used as probes to screen an expression library that was prepared from a highly TGF␤-responsive intestinal epithelial cell line. One of the TGF␤ receptor-interacting proteins isolated was identified to be the mammalian homologue of the LC7 family (mLC7) of dynein light chains (DLCs). This 11-kDa cytoplasmic protein interacts with the TGF␤ receptor complex intracellularly and is phosphorylated on serine residues after ligand-receptor engagement. Forced expression of mLC7-1 induces specific TGF␤ responses, including an activation of Jun N-terminal kinase (JNK), a phosphorylation of c-Jun, and an inhibition of cell growth. Furthermore, TGF␤ induces the recruitment of mLC7-1 to the intermediate chain of dynein. A kinase-deficient form of TGF␤ RII prevents both mLC7-1 phosphorylation and interaction with the dynein intermediate chain (DIC). This is the first demonstration of a link between cytoplasmic dynein and a natural growth inhibitory cytokine. Furthermore, our results suggest that TGF␤ pathway components may use a motor protein light chain as a receptor for the recruitment and transport of specific cargo along microtublules. INTRODUCTIONTransforming growth factor-␤ (TGF␤) is the prototype for the TGF␤ superfamily of highly conserved growth regulatory polypeptides that also includes the activins, inhibins, bone morphogenetic proteins, decapentaplegic (Dpp), nodal, Lefty, and others (Roberts, 1998;Sporn and Vilcek, 2000;Yue and Mulder, 2001). Alterations in the TGF␤ signaling components and pathways have been implicated in a vast array of human pathologies, including cancer (Massague et al., 2000;Sporn and Vilcek, 2000;Derynck et al., 2001).TGF␤ binds to two types of transmembrane serine/threonine kinase receptors (RI and RII) in a heterotetrameric complex, to activate downstream components (Roberts, 1998; Massague et al., 2000;Sporn and Vilcek, 2000;Yue and Mulder, 2001). The Smad family of signaling intermediates plays an important role in mediating TGF␤ responses (Attisano and Wrana, 2000;ten Dijke et al., 2000;Yue and Mulder, 2001). Moreover, TGF␤ has been shown to regulate Ras (Mulder and Morris, 1992;Hartsough et al., 1996;Yue et al., 1998) and several components of the mitogen-activated protein kinase (Mapk) pathways (Hartsough and Mulder, 1995;Frey and Mulder, 1997;Mulder, 2000;Sporn and Vilcek, 2000;Yue and Mulder, 2001). In addition to the Ras/Mapk and Smad pathways, several proteins have been identified based upon their interaction with the TGF␤ receptors (Yue and Mulder, 2001). Furthermore, various Smad-interacting proteins have also been identified, including SARA and Dab2, which interact with both Smads and the TGF␤ receptors (Tsukazaki et al., 1998;Hocevar et al., 2001;Yue and Mulder, 2001).Despite advances in our understanding of the mechanisms by which the Smad and Ras/Mapk cascades mediate some TGF␤ effects, these pathways seem to regulate primarily transcriptional events (Hocevar et al., 1...

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“…It is generally admitted that the light chain portion is engaged in cargo binding and attached to cell organelles (e.g. mitochondria) while contributing to their localization (Makokha et al, 2002;Mok et al, 2001;Williams et al, 2005). Schwarzer et al (2002) reported that DYNLT1 slightly increases the voltage-dependence of VDAC1, indicating that DYNLT1 has the ability to modulate channel properties.…”

Section: Discussionmentioning

confidence: 99%

Phosphorylation of DYNLT1 at Serine 82 Regulates Microtubule Stability and Mitochondrial Permeabilization in Hypoxia

Xue

Zhang

et al. 2013

Molecules and Cells

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Hypoxia-induced microtubule disruption and mitochondrial permeability transition (mPT) are crucial events leading to fatal cell damage and recent studies showed that microtubules (MTs) are involved in the modulation of mitochondrial function. Dynein light chain Tctex-type 1 (DYNLT1) is thought to be associated with MTs and mitochondria. Previously we demonstrated that DYNLT1 knockdown aggravates hypoxia-induced mitochondrial permeabilization, which indicates a role of DYNLT1 in hypoxic cytoprotection. But the underlying regulatory mechanism of DYNLT1 remains illusive. Here we aimed to investigate the phosphorylation alteration of DYNLT1 at serine 82 (S82) in hypoxia (1% O 2 ). We therefore constructed recombinant adenoviruses to generate S82E and S82A mutants, used to transfect H9c2 and HeLa cell lines. Development of hypoxia-induced mPT (MMP examining, Cyt c release and mPT pore opening assay), hypoxic energy metabolism (cellular viability and ATP quantification), and stability of MTs were examined. Our results showed that phosph-S82 (S82-P) expression was increased in early hypoxia; S82E mutation (phosphomimic) aggravated mitochondrial damage, elevated the free tubulin in cytoplasm and decreased the cellular viability; S82A mutation (dephosphomimic) seemed to diminish the hypoxia-induced injury. These data suggest that DYNLT1 phosphorylation at S82 is involved in MTs and mitochondria regulation, and their interaction and cooperation contribute to the cellular hypoxic tolerance. Thus, we provide new insights into a DYNLT1 mechanism in stabilizing MTs and mitochondria, and propose a potential therapeutic target for hypoxia cytoprotective studies.

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Interactions of Cytoplasmic Dynein Light Chains Tctex-1 and LC8 with the Intermediate Chain IC74

Cited by 102 publications

References 41 publications

Arl3 and LC8 regulate dissociation of dynactin from dynein

Arl3 and LC8 regulate dissociation of dynactin from dynein

A Novel Transforming Growth Factor-β Receptor-interacting Protein That Is Also a Light Chain of the Motor Protein Dynein

Phosphorylation of DYNLT1 at Serine 82 Regulates Microtubule Stability and Mitochondrial Permeabilization in Hypoxia

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