Protein kinase A effects of an expressed PRKAR1A mutation associated with aggressive tumors.
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.
Meoli
Elise
E
Section on Endocrinology and Genetics, Program in Developmental Endocrinology and Genetics, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland 20892, USA.
Bossis
Ioannis
I
Cazabat
Laure
L
Mavrakis
Manos
M
Horvath
Anelia
A
Stergiopoulos
Sotiris
S
Shiferaw
Miriam L
ML
Fumey
Glawdys
G
Perlemoine
Karine
K
Muchow
Michael
M
Robinson-White
Audrey
A
Weinberg
Frank
F
Nesterova
Maria
M
Patronas
Yianna
Y
Groussin
Lionel
L
Bertherat
Jérôme
J
Stratakis
Constantine A
CA
D000818:Animals; D019556:COS Cells; D048430:Cell Shape / Q000235:genetics; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit / Q000235:genetics* / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D017353:Gene Deletion; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D009361:Neoplasm Invasiveness / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics*; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D014018:Tissue Distribution; D014162:Transfection
D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; C517834:PRKAR1A protein, human; D021122:Protein Subunits; D012333:RNA, Messenger; D017868:Cyclic AMP-Dependent Protein Kinases