scholarly journals p21-Activated Kinase 5 (Pak5) Localizes to Mitochondria and Inhibits Apoptosis by Phosphorylating BAD

2003 ◽  
Vol 23 (16) ◽  
pp. 5526-5539 ◽  
Author(s):  
Sophie Cotteret ◽  
Zahara M. Jaffer ◽  
Alexander Beeser ◽  
Jonathan Chernoff
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Kinase Activity ◽  
Independent Manner ◽  
Promote Neurite Outgrowth ◽  
P21 Activated Kinase ◽  
Kinase A ◽  
Apoptotic Cascade

ABSTRACT Pak5 is the most recently identified and least understood member of the p21-activated kinase (Pak) family. This kinase is known to promote neurite outgrowth in vitro, but its localization, substrates, and effects on cell survival have not been reported. We show here that Pak5 has unique properties that distinguish it from all other members of the Pak family. First, Pak5, unlike Pak1, cannot complement an STE20 mutation in Saccharomyces cerevisiae. Second, Pak5 binds to the GTPases Cdc42 and Rac, but these GTPases do not regulate Pak5 kinase activity, which is constitutive and stronger than any other Pak. Third, Pak5 prevents apoptosis induced by camptothecin and C2-ceramide by phosphorylating BAD on Ser-112 in a protein kinase A-independent manner and prevents the localization of BAD to mitochondria, thereby inhibiting the apoptotic cascade that leads to apoptosis. Finally, we show that Pak5 itself is constitutively localized to mitochondria, and that this localization is independent of kinase activity or Cdc42 binding. These features make Pak5 unique among the Pak family and suggest that it plays an important role in apoptosis through BAD phosphorylation.

scholarly journals Adeno-Associated Virus Rep78 Protein Interacts with Protein Kinase A and Its Homolog PRKX and Inhibits CREB-Dependent Transcriptional Activation

1998 ◽  
Vol 72 (10) ◽  
pp. 7916-7925 ◽  
Author(s):  
Giovanni Di Pasquale ◽  
Simon N. Stacey
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Transcriptional Activation ◽  
Expression Vector ◽  
Kinase Activity ◽  
Helper Virus ◽  
Regulation Of Transcription ◽  
Adeno Associated Virus ◽  
Kinase A

ABSTRACT Adeno-associated virus (AAV) is a human parvovirus of the genusDependovirus. AAV replication is largely restricted to cells which are coinfected with a helper virus. In the absence of a helper virus, the AAV genome can integrate into a specific chromosomal site where it remains latent until reactivated by superinfection of the host cell with an appropriate helper virus. Replication functions of AAV have been mapped to the Rep68 and Rep78 gene products. Rep proteins demonstrate DNA binding, endonuclease, and helicase activities and are involved in regulation of transcription from both AAV and heterologous promoters. AAV has been associated with suppression of oncogenicity in a range of viral and nonviral tumors. In this study we sought to identify and study cellular protein targets of AAV Rep, in order to develop a better understanding of the various activities of Rep. We used the yeast two-hybrid system to identify HeLa cell proteins that interact with AAV type 2 Rep78. We isolated several strongly interacting clones which were subsequently identified as PRKX (previously named PKX1), a recently described homolog of the protein kinase A (PKA) catalytic subunit (PKAc). The interaction was confirmed in vitro by using pMal-Rep pull-down assays. The region of Rep78 which interacts was mapped to a C-terminal zinc finger-like domain; Rep68, which lacks this domain, did not interact with PRKX. PRKX demonstrated autophosphorylation and kinase activity towards histone H1 and a PKA oligopeptide target. Autophosphorylation was inhibited by interaction with Rep78. In transfection assays, a PRKX expression vector was shown to be capable of activating CREB-dependent transcription. This activation was suppressed by Rep78 but not by Rep68. Since PRKX is a close homolog of PKAc, we investigated whether Rep78 could interact directly with PKAc. pMal-Rep78 was found to associate with purified PKAc and inhibited its kinase activity. Cotransfection experiments demonstrated that Rep78 could block the activation of CREB by a PKAc expression vector. These experiments suggest that AAV may perturb normal cyclic AMP response pathways in infected cells.

scholarly journals Integration of Stress Responses: Modulation of Calcineurin Signaling in Saccharomyces cerevisiae by Protein Kinase A

2004 ◽  
Vol 3 (5) ◽  
pp. 1147-1153 ◽  
Author(s):  
Kimberly A. Kafadar ◽  
Martha S. Cyert
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Stress Responses ◽  
Nuclear Import ◽  
Cellular Response ◽  
Dependent Protein ◽  
Kinase A

ABSTRACT Calcineurin is a Ca2+/calmodulin-dependent protein phosphatase required for Saccharomyces cerevisiae to adapt to a variety of environmental stresses. Once activated, calcineurin dephosphorylates the Zn-finger transcription factor Crz1p/Tcn1p, causing it to accumulate in the nucleus where it activates gene expression. Here we show that cyclic AMP-dependent protein kinase A (PKA) phosphorylates and negatively regulates Crz1p activity by inhibiting its nuclear import. Activation of PKA in vivo decreases Crz1p-dependent transcription. PKA phosphorylates Crz1p in vitro, and we identify specific residues required for this phosphorylation, all of which reside in or adjacent to the nuclear localization signal. Mutation of these residues to alanine results in increased nuclear import of Crz1p and results in higher levels of both basal and Ca2+-induced Crz1p transcriptional activity. PKA regulates the general stress response in yeast and coordinates this response with nutrient availability. In contrast, calcineurin regulates the cellular response to a restricted set of environmental insults. Thus, these studies identify a specific biochemical mechanism through which the activities of multiple stress-activated signaling pathways are integrated in vivo.

scholarly journals Activity, expression and function of a second Drosophila protein kinase A catalytic subunit gene.

Genetics ◽  
1995 ◽  
Vol 141 (4) ◽  
pp. 1507-1520 ◽  
Author(s):  
A Meléndez ◽  
W Li ◽  
D Kalderon
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Essential Gene ◽  
Sequence Similarity ◽  
Catalytic Subunit ◽  
Subunit Gene ◽  
Drosophila Protein ◽  
Pka Catalytic Subunit ◽  
Kinase A

Abstract The DC2 gene was isolated previously on the basis of sequence similarity to DC0, the major Drosophila protein kinase A (PKA) catalytic subunit gene. We show here that the 67-kD Drosophila DC2 protein behaves as a PKA catalytic subunit in vitro. DC2 is transcribed in mesodermal anlagen of early embryos. This expression depends on dorsal but on neither twist nor snail activity. DC2 transcriptional fusions mimic this embryonic expression and are also expressed in subsets of cells in the optic lamina, wing disc and leg discs of third instar larvae. A saturation screen of a small deficiency interval containing DC2 for recessive lethal mutations yielded no DC2 alleles. We therefore isolated new deficiencies to generate deficiency trans-heterozygotes that lacked DC2 activity. These animals were viable and fertile. The absence of DC2 did not affect the viability or phenotype of imaginal disc cells lacking DC0 activity or embryonic hatching of animals with reduced DC0 activity. Furthermore, transgenes expressing DC2 from a DC0 promoter did not efficiently rescue a variety of DC0 mutant phenotypes. These observations indicate that DC2 is not an essential gene and is unlikely to be functionally redundant with DC0, which has multiple unique functions during development.

scholarly journals Complex effects of kinase localization revealed by compartment-specific regulation of protein kinase A activity

2021 ◽  
Author(s):  
Rebecca LaCroix ◽  
Benjamin Lin ◽  
Andre Levchenko
Keyword(s):  
Cell Migration ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Kinase Activity ◽  
Single Cells ◽  
Regulatory Subunit ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Specific Regulation ◽  
Kinase A

SummaryKinase activity in signaling networks frequently depends on regulatory subunits that can both inhibit activity by interacting with the catalytic subunits and target the kinase to distinct molecular partners and subcellular compartments. Here, using a new synthetic molecular interaction system, we show that translocation of a regulatory subunit of the protein kinase A (PKA-R) to the plasma membrane has a paradoxical effect on the membrane kinase activity. It can both enhance it at lower translocation levels, even in the absence of signaling inputs, and inhibit it at higher translocation levels, suggesting its role as a linker that can both couple and decouple signaling processes in a concentration-dependent manner. We further demonstrate that superposition of gradients of PKA-R abundance across single cells can control the directionality of cell migration, reversing it at high enough input levels. Thus complex in vivo patterns of PKA-R localization can drive complex phenotypes, including cell migration.

Invariant phosphorylation of the Saccharomyces cerevisiae Cdc28 protein kinase

1988 ◽  
Vol 8 (7) ◽  
pp. 2976-2979
Author(s):  
J A Hadwiger ◽  
S I Reed
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Kinase Activity ◽  
Specific Protein ◽  
Protein Kinase Activity ◽  
Cycle Arrest ◽  
Phosphorylation Level ◽  
Proposed Regulation ◽  
Specific Protein Kinase

The phosphorylation level of the Saccharomyces cerevisiae Cdc28 protein remained invariant under conditions that resulted in cell cycle arrest in the G1 phase and loss of Cdc28-specific protein kinase activity when the activity was assayed in vitro. These results are in contrast to the proposed regulation of the homologous Cdc2 protein kinase of Schizosaccharomyces pombe.

scholarly journals Membrane-Bound Protein Kinase A Inhibits Smooth Muscle Cell Proliferation In Vitro and In Vivo by Amplifying cAMP–Protein Kinase A Signals

2001 ◽  
Vol 88 (3) ◽  
pp. 319-324 ◽  
Author(s):  
Ciro Indolfi ◽  
Eugenio Stabile ◽  
Carmela Coppola ◽  
Adriana Gallo ◽  
Cinzia Perrino ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Protein Kinase ◽  
Smooth Muscle Cell ◽  
Protein Kinase A ◽  
Membrane Bound ◽  
Proliferation In Vitro ◽  
Kinase A
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