title: Cell-cycle modulation of CK2 activity in tobacco BY-2 cells.
abstract: Protein kinase CK2 is an ubiquitous Ser/Thr kinase essential for cell growth. We have used the highly synchronizable tobacco BY-2 cell line to investigate whether CK2 activity and expression are regulated in a cell cycle phase-dependent manner in higher plants. Specific cDNA probes for tobacco CK2alpha and beta subunits, respectively, and polyclonal antibodies recognising alpha and beta subunits separately, were obtained to determine mRNA and protein levels of both subunits. Our results show that CK2 activity oscillates throughout the cell cycle, peaking at G1/S and M phases, due to a post-translational regulation of the tetrameric enzyme. Additional levels of control of CK2 expression operate in relation to the proliferative state of the cells, including differential accumulation of alpha and beta transcripts and post-transcriptional regulation of protein levels (beta subunit). Moreover, in vivo inhibition of CK2 activity corroborates the requirement of the functional CK2 to progress through the cell division cycle, and suggests that CK2 might play an important role at the G2/M checkpoint.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad Autónoma de Barcelona, Spain.
authors.forename: M C
authors.initials: MC
authors.lastname: Espunya
authors.forename: B
authors.initials: B
authors.lastname: Combettes
authors.forename: J
authors.initials: J
authors.lastname: Dot
authors.forename: N
authors.initials: N
authors.lastname: Chaubet-Gigot
authors.forename: M C
authors.initials: MC
authors.lastname: Martínez
mesh_terms: D000918:Antibody Specificity; D047390:Casein Kinase II; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D010507:Periodicity; D010947:Plants, Toxic; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D012333:RNA, Messenger; D018749:RNA, Plant; D014026:Nicotiana / Q000166:cytology* / Q000201:enzymology; D014230:Triazoles / Q000494:pharmacology
chemical_list: C405354:4,5,6,7-tetrabromobenzotriazole; D018797:Cell Cycle Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D014230:Triazoles; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases