Signaling through Cdk2, importin-alpha and NuMA is required for H2O2-induced mitosis in primary type II pneumocytes.
Proliferation of alveolar type II pneumocytes, the multipotent stem cells of the alveoli, has been implicated in the development of lung adenocarcinoma. Hydrogen peroxide (H(2)O(2)), a potent promoter of signaling cascades, can mediate the transmission of many intracellular signals including those involved in cell proliferation. In this study using rat primary type II pneumocytes, we demonstrate that H(2)O(2) significantly increases mitosis through a pathway that includes cyclin-dependent kinase 2 (Cdk2); importin-alpha, a nuclear trafficking regulator; and nuclear mitotic apparatus protein (NuMA), an essential component in mitotic spindle pole formation. Upon H(2)O(2) treatment, Cdk2 is phosphorylated at position thr-160 leading to increases in importin-alpha and NuMA protein levels and resulting in a significant increase of G(2)/M phase in a roscovatine-dependent manner. Type II pneumocytes transfected with NuMA cDNA also show significant increases in G(2)/M phase, NuMA, Cdk2 thr-160 and importin-alpha expression. These effects were prevented by catalase. These results demonstrate that H(2)O(2) orchestrates a complex signaling network regulating S phase entry, nuclear trafficking and spindle pole formation through activation of Cdk2, importin-alpha, and NuMA. This pathway is essential for H(2)O(2)-induced mitosis in type II pneumocytes.
Radisavljevic
Ziv Manasija
ZM
Department of Environmental Health, Physiology Program, Harvard University, School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA. zradisav@hsph.harvard.edu
González-Flecha
Beatriz
B
Manasija-Radisavljevic
Ziv
Z
D000818:Animals; D042846:CDC2-CDC28 Kinases; D002374:Catalase / Q000494:pharmacology; D018797:Cell Cycle Proteins; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000502:physiology*; D005949:Glucose Oxidase / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008168:Lung / Q000166:cytology / Q000187:drug effects*; D008938:Mitosis / Q000187:drug effects*; D009687:Nuclear Proteins / Q000502:physiology*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011687:Purines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077546:Roscovitine; D028901:alpha Karyopherins / Q000502:physiology*
D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C489081:Numa1 protein, rat; D011687:Purines; D028901:alpha Karyopherins; D000077546:Roscovitine; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase; D002374:Catalase; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495892:Cdk2 protein, rat; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases