Protein Kinase A, which Regulates Intracellular Transport, Forms Complexes with Molecular Motors on Organelles

Kashina, Anna; Семенова, И. В.; Иванов, П. А.; Potekhina, Ekaterina; Zaliapin, Ilya; Rodionov, Vladimir

doi:10.1016/j.cub.2004.10.003

Cited by 50 publications

(69 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…25 Most likely, cytoplasmic vesicle-bound PKA complexes with dynein and kinesin, as has been reported for the intracellular transport of pigment granules. 43 In our study, interfering with the actin skeleton had no effect on apoE secretion, suggesting a distinction between actin-mediated phagocytosis or migration 44,45 and macrophage-mediated protein secretion. …”

Section: Discussionmentioning

confidence: 45%

Secretion of Apolipoprotein E From Macrophages Occurs via a Protein Kinase A– and Calcium-Dependent Pathway Along the Microtubule Network

Kockx

Guo

Huby

et al. 2007

Circulation Research

View full text Add to dashboard Cite

Abstract-Macrophage-specific expression of apolipoprotein (apo)E protects against atherosclerosis; however, the signaling and trafficking pathways regulating secretion of apoE are unknown. We investigated the roles of the actin skeleton, microtubules, protein kinase A (PKA) and calcium (Ca 2ϩ ) in regulating apoE secretion from macrophages. Disrupting microtubules with vinblastine or colchicine inhibited basal secretion of apoE substantially, whereas disruption of the actin skeleton had no effect. Structurally distinct inhibitors of PKA (H89, KT5720, inhibitory peptide PKI 14 -22 ) all decreased basal secretion of apoE by between 50% to 80% (PϽ0.01). Pulse-chase experiments demonstrated that inhibition of PKA reduced the rate of apoE secretion without affecting its degradation. Confocal microscopy and live cell imaging of apoE-green fluorescent protein-transfected RAW macrophages identified apoE-green fluorescent protein in vesicles colocalized with the microtubular network, and inhibition of PKA markedly inhibited vesicular movement. Chelation of intracellular calcium ([Ca 2ϩ ] i ) with 1,2-bis(2-aminophenoxy)ethane-N,N,NЈ,NЈ-tetraacetate-acetoxymethyl ester (BAPTA-AM) inhibited apoE secretion by 77.2% (PϽ0.01). Injection of c57Bl6 apoE ϩ/ϩ bone marrow-derived macrophages into the peritoneum of apoE Ϫ/Ϫ C57Bl6 mice resulted in time-dependent secretion of apoE into plasma, which was significantly inhibited by transient exposure of macrophages to BAPTA-AM and colchicine and less effectively inhibited by H89. We conclude that macrophage secretion of apoE occurs via a PKA-and calcium-dependent pathway along the microtubule network.

show abstract

Section: Discussionmentioning

confidence: 45%

Secretion of Apolipoprotein E From Macrophages Occurs via a Protein Kinase A– and Calcium-Dependent Pathway Along the Microtubule Network

Kockx

Guo

Huby

et al. 2007

Circulation Research

View full text Add to dashboard Cite

show abstract

“…The opposite process occurs during aggregation, when cAMP levels are reduced and melanosomes are transferred from the actin to the microtubule network to be clustered in the cell center (36,38,39). Consistent with these observations, PKA was found to associate with melanosomes and even to form complexes with the respective motor proteins in melanophores (40,41). Whether any of these motor complexes are direct targets of PKA, however, remains to be elucidated.…”

Section: Significancementioning

confidence: 62%

Myosin Va’s adaptor protein melanophilin enforces track selection on the microtubule and actin networks in vitro

Oberhofer

Spieler

Rosenfeld

et al. 2017

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

View full text Add to dashboard Cite

Pigment organelles, or melanosomes, are transported by kinesin, dynein, and myosin motors. As such, melanosome transport is an excellent model system to study the functional relationship between the microtubule-and actin-based transport systems. In mammalian melanocytes, it is well known that the Rab27a/melanophilin/myosin Va complex mediates actin-based transport in vivo. However, pathways that regulate the overall directionality of melanosomes on the actin/microtubule networks have not yet been delineated. Here, we investigated the role of PKA-dependent phosphorylation on the activity of the actin-based Rab27a/melanophilin/myosin Va transport complex in vitro. We found that melanophilin, specifically its C-terminal actin-binding domain (ABD), is a target of PKA. Notably, in vitro phosphorylation of the ABD closely recapitulated the previously described in vivo phosphorylation pattern. Unexpectedly, we found that phosphorylation of the ABD affected neither the interaction of the complex with actin nor its movement along actin tracks. Surprisingly, the phosphorylation state of melanophilin was instead important for reversible association with microtubules in vitro. Dephosphorylated melanophilin preferred binding to microtubules even in the presence of actin, whereas phosphorylated melanophilin associated with actin. Indeed, when actin and microtubules were present simultaneously, melanophilin's phosphorylation state enforced track selection of the Rab27a/melanophilin/ myosin Va transport complex. Collectively, our results unmasked the regulatory dominance of the melanophilin adaptor protein over its associated motor and offer an unexpected mechanism by which filaments of the cytoskeletal network compete for the moving organelles to accomplish directional transport on the cytoskeleton in vivo.melanophilin | myosin Va | intracellular transport | transport regulation

show abstract

“…This demonstrates that a simultaneous docking of Mtap2 to microtubules and TREK-1 is crucial for controlling the microtubule-based transport of the latter. Mtap2 interacts with the kinase PKA (Obar et al, 1989), whose activity is known to control motor protein activity (Kashina et al, 2004). Recruitment of PKA by Mtap2 to close proximity of vesicles containing TREKs, and modulation of adjacent motor proteins by PKA, may provide a molecular basis for the observed effect on TREK trafficking.…”

Section: Discussionmentioning

confidence: 99%

Mtap2 Is a Constituent of the Protein Network That Regulates Twik-Related K⁺Channel Expression and Trafficking

Sandoz¹,

Tardy²,

Thümmler³

et al. 2008

J. Neurosci.

View full text Add to dashboard Cite

Twik-related Kϩ (TREK) channels produce background currents that regulate cell excitability. In vivo, TREK-1 is involved in neuronal processes including neuroprotection against ischemia, general anesthesia, pain perception, and mood. Recently, we demonstrated that A-kinase anchoring protein AKAP150 binds to a major regulatory domain of TREK-1, promoting drastic changes in channel regulation by polyunsaturated fatty acids, pH, and stretch, and by G-protein-coupled receptors to neurotransmitters and hormones. Here, we show that the microtubule-associated protein Mtap2 is another constituent of native TREK channels in the brain. Mtap2 binding to TREK-1 and TREK-2 does not affect directly channel properties but enhances channel surface expression and current density. This effect relies on Mtap2 binding to microtubules. Mtap2 and AKAP150 interacting sites in TREK-1 are distinct and both proteins can dock simultaneously. Their effects on TREK-1 surface expression and activation are cumulative. In neurons, the three proteins are simultaneously detected in postsynaptic dense bodies. AKAP150 and Mtap2 put TREK channels at the center of a complex protein network that finely tunes channel trafficking, addressing, and regulation.

show abstract

Protein Kinase A, which Regulates Intracellular Transport, Forms Complexes with Molecular Motors on Organelles

Cited by 50 publications

References 15 publications

Secretion of Apolipoprotein E From Macrophages Occurs via a Protein Kinase A– and Calcium-Dependent Pathway Along the Microtubule Network

Secretion of Apolipoprotein E From Macrophages Occurs via a Protein Kinase A– and Calcium-Dependent Pathway Along the Microtubule Network

Myosin Va’s adaptor protein melanophilin enforces track selection on the microtubule and actin networks in vitro

Mtap2 Is a Constituent of the Protein Network That Regulates Twik-Related K⁺Channel Expression and Trafficking

Contact Info

Product

Resources

About

Protein Kinase A, which Regulates Intracellular Transport, Forms Complexes with Molecular Motors on Organelles

Cited by 50 publications

References 15 publications

Secretion of Apolipoprotein E From Macrophages Occurs via a Protein Kinase A– and Calcium-Dependent Pathway Along the Microtubule Network

Secretion of Apolipoprotein E From Macrophages Occurs via a Protein Kinase A– and Calcium-Dependent Pathway Along the Microtubule Network

Myosin Va’s adaptor protein melanophilin enforces track selection on the microtubule and actin networks in vitro

Mtap2 Is a Constituent of the Protein Network That Regulates Twik-Related K+Channel Expression and Trafficking

Contact Info

Product

Resources

About

Mtap2 Is a Constituent of the Protein Network That Regulates Twik-Related K⁺Channel Expression and Trafficking