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Dynein light chain 1 (LC8) association enhances microtubule stability and promotes microtubule bundling.

ABSTRACT: BACKGROUND: Dynein Light Chain 1 (LC8) has been shown to pull down tubulin subunits, suggesting that it interacts with microtubules. RESULTS: LC8 decorates microtubules in vitro and in Drosophila embryos, promotes microtubule assembly, and stabilizes microtubules both in vitro and in tissue-cultured cells. CONCLUSION: LC8 stabilizes microtubules. SIGNIFICANCE: Data provide the first evidence of a novel MAP-like function of LC8. Dynein light chain 1 (LC8), a highly conserved protein, is known to bind to a variety of different polypeptides. It functions as a dimer, which is inactivated through phosphorylation at the Ser-88 residue. A loss of LC8 function causes apoptosis in Drosophila embryos, and its overexpression induces malignant transformation of breast cancer cells. Here we show that LC8 binds to tubulin, promotes microtubule assembly, and induces the bundling of reconstituted microtubules in vitro. Furthermore, LC8 decorates microtubules both in Drosophila embryos and in HeLa cells, increases the microtubule stability, and promotes microtubule bundling in these cells. Microtubule stability influences a number of different cellular functions including mitosis and cell differentiation. The LC8 overexpression reduces the susceptibility of microtubules to cold and nocodazole-induced depolymerization in tissue-cultured cells and increases microtubule acetylation, suggesting that LC8 stabilizes microtubules. We also show that LC8 knockdown or transfection with inhibitory peptides destabilizes microtubules and inhibits bipolar spindle assembly in HeLa cells. In addition, LC8 knockdown leads to the mitotic block in HeLa cells. Furthermore, molecular docking analysis using the crystal structures of tubulin and LC8 dimer indicated that the latter may bind at ?-? tubulin junction in a protofilament at sites distinct from the kinesin and dynein binding sites. Together, we provide the first evidence of a novel microtubule-associated protein-like function of LC8 that could explain its reported roles in cellular metastasis and differentiation.

SUBMITTER: Asthana J

PROVIDER: S-EPMC3504791 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature

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Dynein light chain 1 (LC8) association enhances microtubule stability and promotes microtubule bundling.

Asthana Jayant J Kuchibhatla Anuradha A Jana Swadhin Chandra SC Ray Krishanu K Panda Dulal D

The Journal of biological chemistry 20121004 48

<h4>Background</h4>Dynein Light Chain 1 (LC8) has been shown to pull down tubulin subunits, suggesting that it interacts with microtubules.<h4>Results</h4>LC8 decorates microtubules in vitro and in Drosophila embryos, promotes microtubule assembly, and stabilizes microtubules both in vitro and in tissue-cultured cells.<h4>Conclusion</h4>LC8 stabilizes microtubules.<h4>Significance</h4>Data provide the first evidence of a novel MAP-like function of LC8. Dynein light chain 1 (LC8), a highly conser ...[more]

PMID: 23038268

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Project description:Protein-protein interactions (PPIs) formed between short linear motifs and globular domains play important roles in many regulatory and signaling processes but are highly underrepresented in current protein-protein interaction databases. These types of interactions are usually characterized by a specific binding motif that captures the key amino acids shared among the interaction partners. However, the computational proteome-level identification of interaction partners based on the known motif is hindered by the huge number of randomly occurring matches from which biologically relevant motif hits need to be extracted. In this work, we established a novel bioinformatic filtering protocol to efficiently explore interaction network of a hub protein. We introduced a novel measure that enabled the optimization of the elements and parameter settings of the pipeline which was built from multiple sequence-based prediction methods. In addition, data collected from PPI databases and evolutionary analyses were also incorporated to further increase the biological relevance of the identified motif hits. The approach was applied to the dynein light chain LC8, a ubiquitous eukaryotic hub protein that has been suggested to be involved in motor-related functions as well as promoting the dimerization of various proteins by recognizing linear motifs in its partners. From the list of putative binding motifs collected by our protocol, several novel peptides were experimentally verified to bind LC8. Altogether 71 potential new motif instances were identified. The expanded list of LC8 binding partners revealed the evolutionary plasticity of binding partners despite the highly conserved binding interface. In addition, it also highlighted a novel, conserved function of LC8 in the upstream regulation of the Hippo signaling pathway. Beyond the LC8 system, our work also provides general guidelines that can be applied to explore the interaction network of other linear motif binding proteins or protein domains.

Dataset Information

Dynein light chain 1 (LC8) association enhances microtubule stability and promotes microtubule bundling.

Publications

Dynein light chain 1 (LC8) association enhances microtubule stability and promotes microtubule bundling.

Similar Datasets

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