Protein Kinase A: A Master Kinase of Granulosa Cell Differentiation.
Activation of protein kinase A (PKA) by follicle stimulating hormone (FSH) transduces the signal that drives differentiation of ovarian granulosa cells (GCs). An unresolved question is whether PKA is sufficient to initiate the complex program of GC responses to FSH. We compared signaling pathways and gene expression profiles of GCs stimulated with FSH or expressing PKA-CQR, a constitutively active mutant of PKA. Both FSH and PKA-CQR stimulated the phosphorylation of proteins known to be involved in GC differentiation including CREB, ß-catenin, AKT, p42/44 MAPK, GAB2, GSK-3ß, FOXO1, and YAP. In contrast, FSH stimulated the phosphorylation of p38 MAP kinase but PKA-CQR did not. Microarray analysis revealed that 85% of transcripts that were up-regulated by FSH were increased to a comparable extent by PKA-CQR and of the transcripts that were down-regulated by FSH, 76% were also down-regulated by PKA-CQR. Transcripts regulated similarly by FSH and PKA-CQR are involved in steroidogenesis and differentiation, while transcripts more robustly up-regulated by PKA-CQR are involved in ovulation. Thus, PKA, under the conditions of our experimental approach appears to function as a master upstream kinase that is sufficient to initiate the complex pattern of intracellular signaling pathway and gene expression profiles that accompany GC differentiation.
Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Womens Research Institute, University of Pittsburgh, Pittsburgh, 15213, PA, USA.
Pawan
P
Puri
Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Womens Research Institute, University of Pittsburgh, Pittsburgh, 15213, PA, USA.
Lynda
L
Little-Ihrig
Department of Biomedical Informatics, University of Pittsburgh, Pittsburgh, 15206, PA, USA.
Uma
U
Chandran
School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, 99164, WA, USA.
Nathan C
NC
Law
School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, 99164, WA, USA.
Mary
M
Hunzicker-Dunn
Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Womens Research Institute, University of Pittsburgh, Pittsburgh, 15213, PA, USA.
Anthony J
AJ
Zeleznik
D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D005260:Female; D043373:Follicle Stimulating Hormone, Human / Q000378:metabolism*; D005786:Gene Expression Regulation; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D006107:Granulosa Cells / Q000502:physiology*; D006801:Humans; D009154:Mutation / Q000235:genetics; D010053:Ovary / Q000166:cytology*; D051381:Rats; D011919:Rats, Inbred Strains; D015398:Signal Transduction; D013256:Steroids / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D043373:Follicle Stimulating Hormone, Human; D013256:Steroids; D051176:beta Catenin; D017868:Cyclic AMP-Dependent Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D038362:Glycogen Synthase Kinase 3