Membrane depolarization stimulates the proliferation of SH-SY5Y human neuroblastoma cells by increasing retinoblastoma protein (RB) phosphorylation through the activation of cyclin-dependent kinase 2 (Cdk2).
Membrane depolarization causes transmembrane ionic influxes that induce various gene expressions, and is involved in the processes of neuronal differentiation and apoptosis. However, the effect of membrane depolarization on neuronal proliferation has not been established. In this study, we aimed to investigate the effect of membrane depolarization on the proliferation of SH-SY5Y human neuroblastoma cells. Membrane depolarization induced by 50 mM KCl for 5 min significantly increased SH-SY5Y cell numbers and thymidine incorporation at 24 h after depolarization, and increased the phosphorylation and expression of retinoblastoma protein (RB), the activity of Cdk2 (without changing the activities of Cdk4 and Cdk6), and the expressions of cyclin A and cyclin E. Single and repeated depolarization (once a day for 6 days) had similar effects on RB, Cdks, and cyclins levels and activities. In summary, our results suggest that membrane depolarization may stimulate cellular proliferation by augmenting the expression of cyclin E leading to increases in Cdk2 activity and RB phosphorylation.
Seo
Miran
M
Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
Kim
Yeni
Y
Lee
Yun-Il
YI
Kim
So-Young
SY
Ahn
Yong-Min
YM
Kang
Ung Gu
UG
Roh
Myoung-Sun
MS
Kim
Yong-Sik
YS
Juhnn
Yong-Sung
YS
D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology*; D019927:Cyclin E / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2 / Q000378:metabolism*; D051358:Cyclin-Dependent Kinase 4 / Q000378:metabolism; D051361:Cyclin-Dependent Kinase 6 / Q000378:metabolism; D004273:DNA, Neoplasm / Q000096:biosynthesis; D004789:Enzyme Activation; D006801:Humans; D008564:Membrane Potentials; D009447:Neuroblastoma; D010766:Phosphorylation; D011189:Potassium Chloride / Q000494:pharmacology; D016160:Retinoblastoma Protein / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism
D019927:Cyclin E; D004273:DNA, Neoplasm; D016160:Retinoblastoma Protein; D011189:Potassium Chloride; C495911:CDK6 protein, human; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D013936:Thymidine