Activation of protein kinase Czeta mediates luteinizing hormone- or forskolin-induced NGFI-B expression in preovulatory granulosa cells of rat ovary.
We have previously demonstrated that luteinizing hormone (LH) induces a rapid and transient expression of NGFI-B in the ovary. In this report, we investigated the signaling pathway for LH- and forskolin-induced NGFI-B expression in cultured rat granulosa cells of preovulatory follicles. LH- or forskolin-induced NGFI-B expression was suppressed by high dose of protein kinase C (PKC) inhibitor RO 31-8220 (10 microM), but not by low doses RO 31-8220 (0.1-1.0 microM) or adenylate cyclase inhibitor MDL-12,300A, implicating the involvement of atypical PKCs. Kinase assay revealed that LH treatment of granulosa cells resulted in a rapid stimulation of atypical PKCzeta activity. Interestingly, like LH, forskolin was also able to activate PKCzeta. Treatment with the cell-permeable PKCzeta-specific inhibitor pseudosubstrate peptide inhibited LH-or forskolin-induced NGFI-B expression, indicating the essential role of PKCzeta. Consistent with this promise, in granulosa cells depleted of diacylglycerol sensitive PKCs by prolonged treatment with tetradecanoylphobol-13-acetate, LH or forskolin could still induce NGFI-B expression, and RO 31-8220 or the PKCzeta pseudosubstrate peptide inhibited LH- or forskolin-induced NGFI-B expression. Furthermore, overexpression of dominant-negative PKCzeta in primary granulosa cells using a replication-defective adenovirus vector resulted in the suppression of LH- or forskolin-induced NGFI-B expression. Our findings demonstrate that PKCzeta, which is activated by LH or forskolin, contributes to the induction of NGFI-B in granulosa cells of preovulatory follicles.
Park
Jae-Il
JI
Hormone Research Center and School of Biological Sciences & Technology, Chonnam National University, Republic of Korea.
Kim
Sun-Gyun
SG
Chun
Jang-Soo
JS
Seo
You-Mi
YM
Jeon
Mi-Jin
MJ
Ohba
Motoi
M
Kim
Hyun-Jin
HJ
Chun
Sang-Young
SY
D000256:Adenoviridae; D000818:Animals; D005576:Colforsin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D005799:Genes, Dominant; D005822:Genetic Vectors; D006107:Granulosa Cells / Q000187:drug effects* / Q000201:enzymology*; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism; D007986:Luteinizing Hormone / Q000494:pharmacology*; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D010060:Ovulation / Q000187:drug effects*; D010703:Phorbol Esters / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014157:Transcription Factors / Q000378:metabolism*; D000099221:Protein Kinase C zeta
D005576:Colforsin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D004268:DNA-Binding Proteins; D007211:Indoles; D007527:Isoenzymes; D007986:Luteinizing Hormone; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D010703:Phorbol Esters; D011493:Protein Kinase C; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D014157:Transcription Factors; D000099221:Protein Kinase C zeta; C539820:Nr4a1 protein, rat; C064758:Ro 31-8220