Cytoplasmic Dynein Intermediate Chain Phosphorylation Regulates Binding to Dynactin

Vaughan, Patricia S.; Leszyk, John D.; Vaughan, Kevin T.

doi:10.1074/jbc.m102649200

Cited by 124 publications

(159 citation statements)

References 49 publications

(26 reference statements)

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“…Intriguingly, PCTAIRE kinases are themselves subject to regulation by protein kinase A (Graeser et al, 2002). There is also considerable evidence for the regulation by phosphorylation of motor proteins such as dynein (Vaughan et al, 2001) and its adaptor dynactin (Vaughan et al, 2002), which are known to be involved in COPII-dependent export from the ER (Watson et al, 2005) and ER-to-Golgi transport (Presley et al, 1997). There is also evidence that both the COPI and COPII complexes can be phosphorylated (Dudognon et al, 2004;Salama et al, 1997;Sheff et al, 1996), however, PCTAIRE protein kinases were not found to phosphorylate either of these complexes in vitro (data not shown).…”

Section: Discussionmentioning

confidence: 91%

PCTAIRE protein kinases interact directly with the COPII complex and modulate secretory cargo transport

Palmer

Konkel

Stephens

2005

Journal of Cell Science

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The export of secretory cargo from the endoplasmic reticulum is mediated by the COPII complex. In common with other aspects of intracellular transport, this step is regulated by protein kinase signalling. Recruitment of the COPII complex to the membrane is known to require ATP and to be blocked by the protein kinase inhibitor H-89. The identity of the specific protein kinase or kinases involved remains equivocal. Here we show that the Sec23p subunit of COPII interacts with PCTAIRE protein kinases. This interaction is shown using two-hybrid screening, direct binding and immunoprecipitation. Inhibition of PCTAIRE kinase activity by expression of a kinase-dead mutant, or specific depletion of PCTAIRE using RNAi, leads to defects in early secretory pathway function including cargo transport, as well as vesicular-tubular transport carrier (VTC) and Golgi localization. These data show a role for PCTAIRE protein kinase function in membrane traffic through the early secretory pathway.

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Section: Discussionmentioning

confidence: 91%

PCTAIRE protein kinases interact directly with the COPII complex and modulate secretory cargo transport

Palmer

Konkel

Stephens

2005

Journal of Cell Science

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“…Hypothetically, glucose or FFA catabolism could be impaired during lipolysis. However, previous studies have shown that various lipolytic hormones increase glucose oxidation and lactate production and, if anything, that would increase cellular ATP levels (61)(62)(63)(64). Also, fatty acid oxidation has been reported to account for only a very small portion of oxygen consumption and ATP production in adipocytes (51).…”

Section: Discussionmentioning

confidence: 99%

AMP-activated Protein Kinase Is Activated as a Consequence of Lipolysis in the Adipocyte

Gauthier

Miyoshi

Souza

et al. 2008

Journal of Biological Chemistry

225

207

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AMP-activated protein kinase (AMPK) is activated in adipocytes during exercise and other states in which lipolysis is stimulated. However, the mechanism(s) responsible for this effect and its physiological relevance are unclear. To examine these questions, 3T3-L1 adipocytes were treated with cAMP-inducing agents (isoproterenol, forskolin, and isobutylmethylxanthine), which stimulate lipolysis and activate AMPK. When lipolysis was partially inhibited with the general lipase inhibitor orlistat, AMPK activation by these agents was also partially reduced, but the increases in cAMP levels and cAMP-dependent protein kinase (PKA) activity were unaffected. Likewise, small hairpin RNA-mediated silencing of adipose tissue triglyceride lipase inhibited both forskolin-stimulated lipolysis and AMPK activation but not that of PKA. Forskolin treatment increased the AMP:ATP ratio, and this too was reduced by orlistat. When acyl-CoA synthetase, which catalyzes the conversion of fatty acids to fatty acyl-CoA, was inhibited with triacsin C, the increases in both AMPK activity and AMP:ATP ratio were blunted. Isoproterenol-stimulated lipolysis was accompanied by an increase in oxidative stress, an effect that was quintupled in cells incubated with the AMPK inhibitor compound C. The isoproterenol-induced increase in the AMP:ATP ratio was also much greater in these cells. In conclusion, the results indicate that activation of AMPK in adipocytes by cAMP-inducing agents is a consequence of lipolysis and not of PKA activation. They suggest that AMPK activation in this setting is caused by an increase in the AMP:ATP ratio that appears to be due, at least in part, to the acylation of fatty acids. Finally, this AMPK activation appears to restrain the energy depletion and oxidative stress caused by lipolysis. AMP-activated protein kinase (AMPK)2 is a sensor of cellular energy state that responds to metabolic stresses and other regulatory signals. The mechanism of activation of AMPK is a complex phenomenon and is still not fully understood, although it is recognized that it involves phosphorylation of the critical Thr-172 residue of its ␣ catalytic subunit by upstream kinases such as LKB1, Ca 2ϩ -calmodulin-dependent protein kinase kinase, and possibly Tak1, a member of the mitogenactivated protein kinase kinase kinase family (1-5). AMPK is also regulated by AMP allosterically and the current view is that this both increases AMPK activity directly and makes it a poorer substrate for phosphatases (6).The role and regulation of AMPK in muscle, liver, and various cultured cells have been extensively studied. It is now well established that energy depletion because of starvation, hypoxia, and exercise increases the intracellular AMP:ATP ratio and secondarily AMPK activity (7). Upon its activation, a major role of AMPK is to replete cellular energy stores by stimulating processes that generate ATP, such as fatty acid oxidation, and inhibiting ATP-consuming pathways (e.g. lipogenesis, triglyceride synthesis, and gluconeogenesis) that are not acutel...

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“…Splicing sites and a serine-rich region lie within the p150 Glued binding site, suggesting that the entire region is involved in IC regulation. Phosphorylation of Ser-84 in the IC affects p150 Glued binding (46). In this context, it is possible that the presence of the LCs regulates the conformation of N-terminal region of the IC and thus the IC interaction with dynactin.…”

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confidence: 99%

Structural and thermodynamic characterization of a cytoplasmic dynein light chain–intermediate chain complex

Williams

Roulhac²,

Roy³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

116

178

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Cytoplasmic dynein is a microtubule-based motor protein complex that plays important roles in a wide range of fundamental cellular processes, including vesicular transport, mitosis, and cell migration. A single major form of cytoplasmic dynein associates with membranous organelles, mitotic kinetochores, the mitotic and migratory cell cortex, centrosomes, and mRNA complexes. The ability of cytoplasmic dynein to recognize such diverse forms of cargo is thought to be associated with its several accessory subunits, which reside at the base of the molecule. The dynein light chains (LCs) LC8 and TcTex1 form a subcomplex with dynein intermediate chains, and they also interact with numerous protein and ribonucleoprotein partners. This observation has led to the hypothesis that these subunits serve to tether cargo to the dynein motor. Here, we present the structure and a thermodynamic analysis of a complex of LC8 and TcTex1 associated with their intermediate chain scaffold. The intermediate chains effectively block the major putative cargo binding sites within the light chains. These data suggest that, in the dynein complex, the LCs do not bind cargo, in apparent disagreement with a role for LCs in dynein cargo binding interactions.crystal structure ͉ microtubules ͉ molecular transport ͉ protein-protein interaction

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Cytoplasmic Dynein Intermediate Chain Phosphorylation Regulates Binding to Dynactin

Cited by 124 publications

References 49 publications

PCTAIRE protein kinases interact directly with the COPII complex and modulate secretory cargo transport

PCTAIRE protein kinases interact directly with the COPII complex and modulate secretory cargo transport

AMP-activated Protein Kinase Is Activated as a Consequence of Lipolysis in the Adipocyte

Structural and thermodynamic characterization of a cytoplasmic dynein light chain–intermediate chain complex

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