AKAP350 Interaction with cdc42 Interacting Protein 4 at the Golgi Apparatus

The A kinase anchoring protein 350 (AKAP350) is a multiply spliced type II protein kinase A anchoring protein that localizes to the centrosomes in most cells and to the Golgi apparatus in epithelial cells. In the present study, we sought to identify AKAP350 interacting proteins that could yield insights into AKAP350 function at the Golgi apparatus. Using yeast two-hybrid and pull-down assays, we found that AKAP350 interacts with a family of structurally related proteins, including FBP17, FBP17b, and cdc42 interacting protein 4 (CIP4). CIP4 interacts with the GTP-bound form of cdc42, with the Wiscott Aldrich Syndrome group of proteins, and with microtubules, and exerts regulatory effects on cytoskeleton and membrane trafficking. CIP4 is phosphorylated by protein kinase A in vitro, and elevation of intracellular cyclic AMP with forskolin stimulates in situ phosphorylation of CIP4. Our results indicate that CIP4 interacts with AKAP350 at the Golgi apparatus and that either disruption of this interaction by expressing the CIP4 binding domain in AKAP350, or reduction of AKAP350 expression by RNA interference leads to changes in Golgi structure. The results suggest that AKAP350 and CIP4 influence the maintenance of normal Golgi apparatus structure.

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A-kinase anchoring protein 8L interacts with mTORC1 and promotes cell growth

Journal of Biological Chemistry ◽

10.1074/jbc.ac120.012595 ◽

2020 ◽

Vol 295 (23) ◽

pp. 8096-8105 ◽

Cited By ~ 2

Author(s):

Chase H. Melick ◽

Delong Meng ◽

Jenna L. Jewell

Keyword(s):

Protein Kinase ◽

Cell Growth ◽

Protein Kinase A ◽

Terminal Region ◽

Regulatory Subunit ◽

Interacting Protein ◽

Regulatory Subunits ◽

Anchoring Protein ◽

Regulate Cell Growth ◽

Kinase A

mTOR complex 1 (mTORC1) senses nutrients to mediate anabolic processes within the cell. Exactly how mTORC1 promotes cell growth remains unclear. Here, we identified a novel mTORC1-interacting protein called protein kinase A anchoring protein 8L (AKAP8L). Using biochemical assays, we found that the N-terminal region of AKAP8L binds to mTORC1 in the cytoplasm. Importantly, loss of AKAP8L decreased mTORC1-mediated processes such as translation, cell growth, and cell proliferation. AKAPs anchor protein kinase A (PKA) through PKA regulatory subunits, and we show that AKAP8L can anchor PKA through regulatory subunit Iα. Reintroducing full-length AKAP8L into cells restored mTORC1-regulated processes, whereas reintroduction of AKAP8L missing the N-terminal region that confers the interaction with mTORC1 did not. Our results suggest a multifaceted role for AKAPs in the cell. We conclude that mTORC1 appears to regulate cell growth, perhaps in part through AKAP8L.

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Anchoring of Protein Kinase A-Regulatory Subunit IIα to Subapically Positioned Centrosomes Mediates Apical Bile Canalicular Lumen Development in Response to Oncostatin M but Not cAMP

Molecular Biology of the Cell ◽

10.1091/mbc.e06-08-0732 ◽

2007 ◽

Vol 18 (7) ◽

pp. 2745-2754 ◽

Cited By ~ 8

Author(s):

Kacper A. Wojtal ◽

Dick Hoekstra ◽

Sven C.D. van IJzendoorn

Keyword(s):

Protein Kinase ◽

Protein Kinase A ◽

Membrane Trafficking ◽

Oncostatin M ◽

Regulatory Subunit ◽

Apical Surface ◽

Dependent Manner ◽

Anchoring Protein ◽

Pka Regulatory Subunit ◽

Kinase A

Oncostatin M and cAMP signaling stimulate apical surface-directed membrane trafficking and apical lumen development in hepatocytes, both in a protein kinase A (PKA)-dependent manner. Here, we show that oncostatin M, but not cAMP, promotes the A-kinase anchoring protein (AKAP)-dependent anchoring of the PKA regulatory subunit (R)IIα to subapical centrosomes and that this requires extracellular signal-regulated kinase 2 activation. Stable expression of the RII-displacing peptide AKAP-IS, but not a scrambled peptide, inhibits the association of RIIα with centrosomal AKAPs and results in the repositioning of the centrosome from a subapical to a perinuclear location. Concomitantly, common endosomes, but not apical recycling endosomes, are repositioned from a subapical to a perinuclear location, without significant effects on constitutive or oncostatin M-stimulated basolateral-to-apical transcytosis. Importantly, however, the expression of the AKAP-IS peptide completely blocks oncostatin M-, but not cAMP-stimulated apical lumen development. Together, the data suggest that centrosomal anchoring of RIIα and the interrelated subapical positioning of these centrosomes is required for oncostatin M-, but not cAMP-mediated, bile canalicular lumen development in a manner that is uncoupled from oncostatin M-stimulated apical lumen-directed membrane trafficking. The results also imply that multiple PKA-mediated signaling pathways control apical lumen development and that subapical centrosome positioning is important in some of these pathways.

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In vitro phosphorylation of human complement factor C3 by protein kinase A and protein kinase C. Effects on the classical and alternative pathways.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)39892-8 ◽

1990 ◽

Vol 265 (5) ◽

pp. 2941-2946

Author(s):

P O Forsberg ◽

S C Martin ◽

B Nilsson ◽

P Ekman ◽

U R Nilsson ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Protein Kinase A ◽

Complement Factor ◽

Human Complement ◽

Alternative Pathways ◽

Kinase C ◽

Complement Factor C3 ◽

Kinase A

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

Genetics ◽

10.1093/genetics/141.4.1507 ◽

1995 ◽

Vol 141 (4) ◽

pp. 1507-1520 ◽

Cited By ~ 5

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.

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