SQSTM1/p62 Interacts with HDAC6 and Regulates Deacetylase Activity (original) (raw)
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HDAC6 controls autophagosome maturation essential for ubiquitin-selective quality-control autophagy
Embo Journal, 2010
Autophagy is primarily considered a non-selective degradation process induced by starvation. Nutrient-independent basal autophagy, in contrast, imposes intracellular QC by selective disposal of aberrant protein aggregates and damaged organelles, a process critical for suppressing neurodegenerative diseases. The molecular mechanism that distinguishes these two fundamental autophagic responses, however, remains mysterious. Here, we identify the ubiquitin-binding deacetylase, histone deacetylase-6 (HDAC6), as a central component of basal autophagy that targets protein aggregates and damaged mitochondria. Surprisingly, HDAC6 is not required for autophagy activation; rather, it controls the fusion of autophagosomes to lysosomes. HDAC6 promotes autophagy by recruiting a cortactin-dependent, actin-remodelling machinery, which in turn assembles an F-actin network that stimulates autophagosome-lysosome fusion and substrate degradation. Indeed, HDAC6 deficiency leads to autophagosome maturation failure, protein aggregate build-up, and neurodegeneration. Remarkably, HDAC6 and F-actin assembly are completely dispensable for starvation-induced autophagy, uncovering the fundamental difference of these autophagic modes. Our study identifies HDAC6 and the actin cytoskeleton as critical components that define QC autophagy and uncovers a novel regulation of autophagy at the level of autophagosome-lysosome fusion.
Cell, 2003
One critical process known to involve both dynein Duke University motors and protein ubiquitination is the management of Durham, North Carolina 27710 misfolded protein aggregates. Misfolded proteins resulting from genetic mutations, inappropriate protein assembly, aberrant modifications, and environmental Summary stress are the inevitable byproducts of biogenesis. More than simply being nonfunctional, misfolded proteins are The efficient clearance of cytotoxic misfolded protein prone to forming aggregates that can interfere with noraggregates is critical for cell survival. Misfolded promal cellular function (Plemper and Wolf, 1999). Thus, tein aggregates are transported and removed from misfolded proteins are closely monitored, processed, the cytoplasm by dynein motors via the microtubule and degraded to prevent their accumulation in cells. The network to a novel organelle termed the aggresome degradation of misfolded proteins, which are recognized where they are processed. However, the means by which and often polyubiquitinated by a complex network of dynein motors recognize misfolded protein cargo, and proteins, is carried out primarily by the proteasome the cellular factors that regulate aggresome formation, (reviewed in Kopito, 1997). However, once aggregated, remain unknown. We have discovered that HDAC6, a misfolded proteins are not degraded efficiently by promicrotubule-associated deacetylase, is a component teasome machinery. As aggregated proteins are toxic, of the aggresome. We demonstrate that HDAC6 has their efficient disposal is essential for cell survival the capacity to bind both polyubiquitinated misfolded (reviewed in Kopito, 2000). In fact, failure to degrade proteins and dynein motors, thereby acting to recruit misfolded and aggregated proteins is a dominant conmisfolded protein cargo to dynein motors for transport tributing factor to neuronal cell death in many neurodeto aggresomes. Indeed, cells deficient in HDAC6 fail generative diseases (Thomas et al., 1995; Lam et al., to clear misfolded protein aggregates from the cyto-2000). plasm, cannot form aggresomes properly, and are hy-
PLoS ONE, 2012
In this study we report that, in response to proteasome inhibition, the E3-Ubiquitin ligase TRIM50 localizes to and promotes the recruitment and aggregation of polyubiquitinated proteins to the aggresome. Using Hdac6-deficient mouse embryo fibroblasts (MEF) we show that this localization is mediated by the histone deacetylase 6, HDAC6. Whereas Trim50-deficient MEFs allow pinpointing that the TRIM50 ubiquitin-ligase regulates the clearance of polyubiquitinated proteins localized to the aggresome. Finally we demonstrate that TRIM50 colocalizes, interacts with and increases the level of p62, a multifunctional adaptor protein implicated in various cellular processes including the autophagy clearance of polyubiquitinated protein aggregates. We speculate that when the proteasome activity is impaired, TRIM50 fails to drive its substrates to the proteasome-mediated degradation, and promotes their storage in the aggresome for successive clearance. Citation: Fusco C, Micale L, Egorov M, Monti M, D'Addetta EV, et al. (2012) The E3-Ubiquitin Ligase TRIM50 Interacts with HDAC6 and p62, and Promotes the Sequestration and Clearance of Ubiquitinated Proteins into the Aggresome. PLoS ONE 7(7): e40440.
Histone Deacetylase 6 Regulates Growth Factor-Induced Actin Remodeling and Endocytosis
Molecular and Cellular Biology, 2007
Histone deacetylase 6 (HDAC6) is a cytoplasmic deacetylase that uniquely catalyzes α-tubulin deacetylation and promotes cell motility. However, the mechanism underlying HDAC6-dependent cell migration and the role for microtubule acetylation in motility are not known. Here we show that HDAC6-induced global microtubule deacetylation was not sufficient to stimulate cell migration. Unexpectedly, in response to growth factor stimulation, HDAC6 underwent rapid translocation to actin-enriched membrane ruffles and subsequently became associated with macropinosomes, the vesicles for fluid-phase endocytosis. Supporting the importance of these associations, membrane ruffle formation, macropinocytosis, and cell migration were all impaired in HDAC6-deficient cells. Conversely, elevated HDAC6 levels promoted membrane ruffle formation with a concomitant increase in macropinocytosis and motility. In search for an HDAC6 target, we found that heat shock protein 90 (Hsp90), another prominent substrate...
2012
Background: Misfolded protein aggregates are recruited to the aggresome by a protein complex consisting of histone deacetylase 6 (HDAC6). Results: The ubiquitin-binding domain (ZnF-UBP) of HDAC6 binds to ubiquitin C termini generated by ataxin-3. Conclusion: The exposure of ubiquitin C termini within protein aggregates enables HDAC6 recognition. Significance: This study provides the role of HDAC6 in aggresome formation and suggests a novel ubiquitin-mediated signaling pathway.
HDAC6 Modulates Cell Motility by Altering the Acetylation Level of Cortactin
Molecular Cell, 2007
Histone deacetylase 6 (HDAC6) is a tubulin-specific deacetylase that regulates microtubuledependent cell movement. In this study, we identify the F-actin-binding protein, cortactin, as a HDAC6 substrate. We demonstrate that HDAC6 binds cortactin and that overexpression of HDAC6 leads to hypoacetylation of cortactin, while inhibition of HDAC6 activity leads to cortactin hyperacetylation. HDAC6 alters the ability of cortactin to bind F-actin by modulating a "charge patch" in its repeat region. Introduction of charge-preserving or charge-neutralizing mutations in this cortactin repeat region correlates with the gain or loss of F-actin binding ability, respectively. Cells expressing a charge-neutralizing cortactin mutant were less motile than control cells or cells expressing a charge-preserving mutant. These findings suggest that, in addition to its role in microtubule-dependent cell motility, HDAC6 influences actin-dependent cell motility by altering the acetylation status of cortactin, which, in turn, changes the F-actin binding activity of cortactin.
iScience, 2021
Stress-coupled NEDDylation potentially regulates the aggregation of nuclear proteins, which could protect the nuclear ubiquitin-proteasome system from proteotoxic stress. However, it remains unclear how NEDDylation controls proteinaggregation responses to diverse stress conditions. Here, we identified HDAC6 as a direct NEDD8-binding partner that regulates the formation of aggresomelike bodies (ALBs) containing NEDDylated cytosolic protein aggregates during ubiquitin stress. HDAC6 colocalizes with stress-induced ALBs, and HDAC6 inhibition suppresses ALBs formation, but not stress-induced NEDDylation, suggesting that HDAC6 carries NEDDylated-proteins to generate ALBs. Then, we monitored the ALBs-associated proteostasis network and found that p62 directly controls ALBs formation as an acceptor of NEDDylated cytosolic aggregates. Interestingly, we also observed that ALBs are highly condensed in chloroquine-treated cells with impaired autophagic flux, indicating that ALBs rely on autophagy. Collectively, our data suggest that NEDD8, HDAC6, and p62 are involved in the management of proteotoxic stress by forming cytosolic ALBs coupled to the aggresome-autophagy flux.
Journal of Biological Chemistry, 2007
Protein degradation by basal constitutive autophagy is important to avoid accumulation of polyubiquitinated protein aggregates and development of neurodegenerative diseases. The polyubiquitin-binding protein p62/SQSTM1 is degraded by autophagy. It is found in cellular inclusion bodies together with polyubiquitinated proteins and in cytosolic protein aggregates that accumulate in various chronic, toxic, and degenerative diseases. Here we show for the first time a direct interaction between p62 and the autophagic effector proteins LC3A and -B and the related ␥-aminobutyrate receptor-associated protein and ␥-aminobutyrate receptor-associated-like proteins. The binding is mediated by a 22-residue sequence of p62 containing an evolutionarily conserved motif. To monitor the autophagic sequestration of p62-and LC3-positive bodies, we developed a novel pH-sensitive fluorescent tag consisting of a tandem fusion of the red, acid-insensitive mCherry and the acid-sensitive green fluorescent proteins. This approach revealed that p62-and LC3-positive bodies are degraded in autolysosomes. Strikingly, even rather large p62-positive inclusion bodies (2 m diameter) become degraded by autophagy. The specific interaction between p62 and LC3, requiring the motif we have mapped, is instrumental in mediating autophagic degradation of the p62-positive bodies. We also demonstrate that the previously reported aggresome-like induced structures containing ubiquitinated proteins in cytosolic bodies are dependent on p62 for their formation. In fact, p62 bodies and these structures are indistinguishable. Taken together, our results clearly suggest that p62 is required both for the formation and the degradation of polyubiquitin-containing bodies by autophagy.
International Journal of Molecular Sciences
The fidelity of actin dynamics relies on protein quality control, but the underlying molecular mechanisms are poorly defined. During mitosis, the cochaperone BCL2-associated athanogene 3 (BAG3) modulates cell rounding, cortex stability, spindle orientation, and chromosome segregation. Mitotic BAG3 shows enhanced interactions with its preferred chaperone partner HSPB8, the autophagic adaptor p62/SQSTM1, and HDAC6, a deacetylase with cytoskeletal substrates. Here, we show that depletion of BAG3, HSPB8, or p62/SQSTM1 can recapitulate the same inhibition of mitotic cell rounding. Moreover, depletion of either of these proteins also interfered with the dynamic of the subcortical actin cloud that contributes to spindle positioning. These phenotypes were corrected by drugs that limit the Arp2/3 complex or HDAC6 activity, arguing for a role for BAG3 in tuning branched actin network assembly. Mechanistically, we found that cortactin acetylation/deacetylation is mitotically regulated and is c...