Structure and function of the human sperm-specific isoform of protein kinase A (PKA) catalytic subunit Cα2

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.

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Protein Kinase A Regulates MYC Protein through Transcriptional and Post-translational Mechanisms in a Catalytic Subunit Isoform-specific Manner

Journal of Biological Chemistry ◽

10.1074/jbc.m112.432377 ◽

2013 ◽

Vol 288 (20) ◽

pp. 14158-14169 ◽

Cited By ~ 24

Author(s):

Achuth Padmanabhan ◽

Xiang Li ◽

Charles J. Bieberich

Keyword(s):

Protein Kinase ◽

Protein Kinase A ◽

Term Effect ◽

Catalytic Subunit ◽

Short Term ◽

Catalytic Subunits ◽

Multiple Substrates ◽

Pka Catalytic Subunit ◽

Kinase A ◽

In Cells

MYC levels are tightly regulated in cells, and deregulation is associated with many cancers. In this report, we describe the existence of a MYC-protein kinase A (PKA)-polo-like kinase 1 (PLK1) signaling loop in cells. We report that sequential MYC phosphorylation by PKA and PLK1 protects MYC from proteasome-mediated degradation. Interestingly, short term pan-PKA inhibition diminishes MYC level, whereas prolonged PKA catalytic subunit α (PKACα) knockdown, but not PKA catalytic subunit β (PKACβ) knockdown, increases MYC. We show that the short term effect of pan-PKA inhibition on MYC is post-translational and the PKACα-specific long term effect on MYC is transcriptional. These data also reveal distinct functional roles among PKA catalytic isoforms in MYC regulation. We attribute this effect to differential phosphorylation selectivity among PKA catalytic subunits, which we demonstrate for multiple substrates. Further, we also show that MYC up-regulates PKACβ, transcriptionally forming a proximate positive feedback loop. These results establish PKA as a regulator of MYC and highlight the distinct biological roles of the different PKA catalytic subunits.

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c-MYC activates protein kinase A (PKA) by direct transcriptional activation of the PKA catalytic subunit beta (PKA-Cβ) gene

Oncogene ◽

10.1038/sj.onc.1205986 ◽

2002 ◽

Vol 21 (51) ◽

pp. 7872-7882 ◽

Cited By ~ 27

Author(s):

Kou-Juey Wu ◽

Michela Mattioli ◽

Herbert C Morse ◽

Riccardo Dalla-Favera

Keyword(s):

Protein Kinase ◽

Protein Kinase A ◽

Transcriptional Activation ◽

Catalytic Subunit ◽

Pka Catalytic Subunit ◽

Kinase A

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Regulation of NT-PGC-1α Subcellular Localization and Function by Protein Kinase A-dependent Modulation of Nuclear Export by CRM1

Journal of Biological Chemistry ◽

10.1074/jbc.m109.083121 ◽

2010 ◽

Vol 285 (23) ◽

pp. 18039-18050 ◽

Cited By ~ 58

Author(s):

Ji Suk Chang ◽

Peter Huypens ◽

Yubin Zhang ◽

Chelsea Black ◽

Anastasia Kralli ◽

...

Keyword(s):

Protein Kinase ◽

Subcellular Localization ◽

Protein Kinase A ◽

Nuclear Export ◽

And Function ◽

Kinase A

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Modulation of Regulatory and Catalytic Subunit Levels of cAMP-Dependent Protein Kinase A in Anterior Pituitary Cells in Response to Direct Activation of Protein Kinases A and C or after GnRH Stimulation

Neuroendocrinology ◽

10.1159/000127042 ◽

1995 ◽

Vol 62 (5) ◽

pp. 514-522 ◽

Cited By ~ 15

Author(s):

Ghislaine Garrel ◽

Richard Delahaye ◽

Brian A. Hemmings ◽

Raymond Counis

Keyword(s):

Protein Kinase ◽

Protein Kinase A ◽

Protein Kinases ◽

Anterior Pituitary ◽

Catalytic Subunit ◽

Pituitary Cells ◽

Dependent Protein Kinase ◽

Camp Dependent Protein Kinase ◽

Dependent Protein ◽

Kinase A

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Cytoplasmic catalytic subunit of protein kinase A mediates cross-repression by NF-kappa B and the glucocorticoid receptor

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.220413297 ◽

2000 ◽

Vol 97 (22) ◽

pp. 11893-11898 ◽

Cited By ~ 90

Author(s):

V. Doucas ◽

Y. Shi ◽

S. Miyamoto ◽

A. West ◽

I. Verma ◽

...

Keyword(s):

Protein Kinase ◽

Glucocorticoid Receptor ◽

Protein Kinase A ◽

Catalytic Subunit ◽

Nf Kappa B ◽

Kinase A

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The activation of the chymotrypsin-like activity of the proteasome is regulated by soluble adenyl cyclase/cAMP/protein kinase A pathway and required for human sperm capacitation

MHR Basic science of reproductive medicine ◽

10.1093/molehr/gaz037 ◽

2019 ◽

Vol 25 (10) ◽

pp. 587-600 ◽

Cited By ~ 2

Author(s):

Héctor Zapata-Carmona ◽

Lina Barón ◽

Lidia M Zuñiga ◽

Emilce Silvina Díaz ◽

Milene Kong ◽

...

Keyword(s):

Protein Kinase ◽

Protein Kinase A ◽

Current Knowledge ◽

Human Sperm ◽

Adenyl Cyclase ◽

Sperm Capacitation ◽

Time Treatment ◽

Proteasome Subunits ◽

Pka Pathway ◽

Kinase A

Abstract One of the first events of mammalian sperm capacitation is the activation of the soluble adenyl cyclase/cAMP/protein kinase A (SACY/cAMP/PKA) pathway. Here, we evaluated whether the increase in PKA activity at the onset of human sperm capacitation is responsible for the activation of the sperm proteasome and whether this activation is required for capacitation progress. Viable human sperm were incubated with inhibitors of the SACY/cAMP/PKA pathway. The chymotrypsin-like activity of the sperm proteasome was evaluated using a fluorogenic substrate. Sperm capacitation status was evaluated using the chlortetracycline assay and tyrosine phosphorylation. To determine whether proteasomal subunits were phosphorylated by PKA, the proteasome was immunoprecipitated and tested on a western blot using an antibody against phosphorylated PKA substrates. Immunofluorescence microscopy analysis and co-immunoprecipitation (IPP) were used to investigate an association between the catalytic subunit alpha of PKA (PKA-Cα) and the proteasome. The chymotrypsin-like activity of the sperm proteasome significantly increased after 5 min of capacitation (P < 0.001) and remained high for the remaining incubation time. Treatment with H89, KT5720 or KH7 significantly decreased the chymotrypsin-like activity of the proteasome (P < 0.001). IPP experiments indicated that PKA inhibition significantly modified phosphorylation of proteasome subunits. In addition, PKA-Cα colocalized with the proteasome in the equatorial segment and in the connecting piece, and co-immunoprecipitated with the proteasome. This is the first demonstration of sperm proteasome activity being directly regulated by SACY/PKA-Cα. This novel discovery extends our current knowledge of sperm physiology and may be used to manage sperm capacitation during assisted reproductive technology procedures.

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