Protein kinase A effects of an expressed PRKAR1A mutation associated with aggressive tumors.

Abstract

Most PRKAR1A tumorigenic mutations lead to nonsense mRNA that is decayed; tumor formation has been associated with an increase in type II protein kinase A (PKA) subunits. The IVS6+1G>T PRKAR1A mutation leads to a protein lacking exon 6 sequences [R1 alpha Delta 184-236 (R1 alpha Delta 6)]. We compared in vitro R1 alpha Delta 6 with wild-type (wt) R1 alpha. We assessed PKA activity and subunit expression, phosphorylation of target molecules, and properties of wt-R1 alpha and mutant (mt) R1 alpha; we observed by confocal microscopy R1 alpha tagged with green fluorescent protein and its interactions with Cerulean-tagged catalytic subunit (C alpha). Introduction of the R1 alpha Delta 6 led to aberrant cellular morphology and higher PKA activity but no increase in type II PKA subunits. There was diffuse, cytoplasmic localization of R1 alpha protein in wt-R1 alpha- and R1 alpha Delta 6-transfected cells but the former also exhibited discrete aggregates of R1 alpha that bound C alpha; these were absent in R1 alpha Delta 6-transfected cells and did not bind C alpha at baseline or in response to cyclic AMP. Other changes induced by R1 alpha Delta 6 included decreased nuclear C alpha. We conclude that R1 alpha Delta 6 leads to increased PKA activity through the mt-R1 alpha decreased binding to C alpha and does not involve changes in other PKA subunits, suggesting that a switch to type II PKA activity is not necessary for increased kinase activity or tumorigenesis.

• Authors: Elise Meoli, Ioannis Bossis, Laure Cazabat, Manos Mavrakis, Anelia Horvath, Sotiris Stergiopoulos, Miriam L Shiferaw, Glawdys Fumey, Karine Perlemoine, Michael Muchow, Audrey Robinson-White, Frank Weinberg, Maria Nesterova, Yianna Patronas, Lionel Groussin, Jérôme Bertherat, Constantine A Stratakis
• Journal: Cancer research (Cancer Res) Vol. 68 Issue 9 Pg. 3133-41 (May 01 2008) ISSN: 1538-7445 [Electronic] United States
• PMID: 18451138 (Publication Type: Journal Article, Research Support, N.I.H., Intramural, Research Support, Non-U.S. Gov't)

Chemical References

• Cyclic AMP-Dependent Protein Kinase RIalpha Subunit
• PRKAR1A protein, human
• Protein Subunits
• RNA, Messenger
• Cyclic AMP-Dependent Protein Kinases

Topics

• Animals
• COS Cells
• Cell Shape (genetics)
• Cells, Cultured
• Chlorocebus aethiops
• Cyclic AMP-Dependent Protein Kinase RIalpha Subunit (genetics, metabolism)
• Cyclic AMP-Dependent Protein Kinases (genetics, metabolism, physiology)
• Gene Deletion
• HeLa Cells
• Humans
• Mutation
• Neoplasm Invasiveness (genetics)
• Neoplasms (genetics)
• Protein Binding
• Protein Subunits (metabolism)
• RNA, Messenger (metabolism)
• Tissue Distribution
• Transfection