GSK3beta modulates PACAP-induced neuritogenesis in PC12 cells by acting downstream of Rap1 in a caveolae-dependent manner.
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neurotrophic peptide. Here, we show that PACAP recruits Rap1 into caveolin-enriched membrane subdomains in PC12 cells and activates Rap1, nuclear ERK1/2, Elk-1 and CREB in a caveolae-dependent manner. We reveal that GSK3beta is a novel modulator in PACAP signalling. PACAP induces phosphorylation of serine 9 in GSK3beta, which is inhibited by silencing Rap1. Lithium and valproate promote but wortmannin and LY294002 attenuate PACAP-induced phosphorylation of both GSK3beta and ERK1/2, whereas MEK inhibitor PD98059 inhibits nerve growth factor- but not PACAP-induced phosphorylation of GSK3beta, suggesting that GSK3beta operates downstream of Rapt 1 but upstream of ERK1/2 in PACAP signalling. Inhibition or stimulation of GSK3beta results in a 2-fold increase and 6-fold decrease in PACAP-induced neurite outgrowth, respectively. These results reveal an important role of caveolae in the signal transduction of PACAP and that GSK3beta is a critical regulator in PACAP-induced neuronal differentiation.
Zhang
Weishi
W
Department of Biochemistry, Yong Loo Lin of Medicine, The National University of Singapore, 8 Medical Drive, Singapore, 117597, Singapore.
Smith
Adam
A
Liu
Jun-ping
JP
Cheung
Nam Sang
NS
Zhou
Shufeng
S
Liu
Ke
K
Li
Qiu-Tian
QT
Duan
Wei
W
D000818:Animals; D021941:Caveolae / Q000187:drug effects / Q000378:metabolism*; D051242:Caveolin 1 / Q000276:immunology; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D008094:Lithium / Q000494:pharmacology; D020935:MAP Kinase Signaling System; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D016501:Neurites / Q000187:drug effects / Q000378:metabolism*; D016716:PC12 Cells; D010766:Phosphorylation; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000378:metabolism*; D034741:RNA, Small Interfering; D051381:Rats; D015398:Signal Transduction; D013997:Time Factors; D014635:Valproic Acid / Q000494:pharmacology; D020827:rap1 GTP-Binding Proteins / Q000378:metabolism*
D051242:Caveolin 1; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D034741:RNA, Small Interfering; D014635:Valproic Acid; D008094:Lithium; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D048052:Mitogen-Activated Protein Kinase 3; D038362:Glycogen Synthase Kinase 3; D020827:rap1 GTP-Binding Proteins