Microtubule disruption stimulates P-body formation

Abstract

Processing bodies (P-bodies) are subcellular ribonucleoprotein (RNP) granules that have been hypothesized to be sites of mRNA degradation, mRNA translational control, and/or mRNA storage. Importantly, P-bodies are conserved from yeast to mammals and contain a common set of evolutionarily conserved protein constituents. P-bodies are dynamic structures and their formation appears to fluctuate in correlation with alterations in mRNA metabolism. Despite these observations, little is understood about how P-body structures are formed within the cell. In this study, we demonstrate a relationship between P-bodies and microtubules in the budding yeast, Saccharomyces cerevisiae. First, we demonstrate that disruption of microtubules by treatment with the drug benomyl leads to aggregation of P-body components. Consistent with this finding, we also demonstrate that disruption of microtubules by a temperature-sensitive allele of the major a tubulin, TUB1 (tub1-724) stimulates P-body formation. Second, we find that the a-tubulin protein Tub1 colocalizes with P-bodies upon microtubule destabilization. Third, we determine that a putative tubulin tyrosine ligase, encoded by YBR094W, is a protein component of P-bodies, providing additional evidence for a physical connection between P-bodies and microtubules. Finally, we establish that P-bodies formed by microtubule destabilization fail to correlate with global changes in the stability of mRNA or in general mRNA translation. These findings demonstrate that the aggregation of P-body components is linked to the intracellular microtubule network, and, further, that P-bodies formed by disruption of microtubules aggregate independent of broad alterations in either mRNA decay or mRNA translation.

General and MicroRNA-Mediated mRNA Degradation Occurs on Ribosome Complexes in Drosophila Cells

“…This clearly indicates that the aggregation into a ribosome free state is not a prerequisite for their degradation. This finding is also consistent with the observation that mRNA degradation can be uncoupled from P-body formation (80)(81)(82)(83). Future experiments investigating the kinetics of mRNA degradation and translation on a transcriptome-wide level will allow a precise quantitative conclusion of which fraction of each transcript is degraded on the ribosome.…”

Interactions of subunit CCT3 in the yeast chaperonin CCT/TRiC with Q/N-rich proteins revealed by high-throughput microscopy analysis

“…The appearance of P-bodies in the MA3 strains could reflect a general response to stress caused by the mutation because it was shown that exposure of S. cerevisiae cells to various forms of stress, such as glucose deprivation or hypotonic shock, can cause P-body formation (18). P-body formation can also be stimulated by microtubule disruption (20). Indeed, treating wild-type cells with benomyl (a β-tubulin polymerization inhibitor) and/or latruncilin-A (an actin polymerization inhibitor) was found to cause P-body formation (20).…”

“…P-body formation can also be stimulated by microtubule disruption (20). Indeed, treating wild-type cells with benomyl (a β-tubulin polymerization inhibitor) and/or latruncilin-A (an actin polymerization inhibitor) was found to cause P-body formation (20). Formation of P-bodies in S. cerevisiae can also be induced by overexpression or deletion of some of their key components (18).…”

mRNP granules

“…For instance, microtubule depolymerizing drugs prevent assembly of large stress granules 39,40 and germ granules in early zebrafish embryos, 41 whereas P-bodies become larger, and less mobile. 42,43 Specific dynein and kinesin motor proteins also localize in stress granules, and appear to facilitate assembly and disassembly of stress granules, respectively. 40 Dynein proteins also increase P-body assembly under stress.…”