title: Influence of S100A6 on CacyBP/SIP Phosphorylation and Elk-1 Transcriptional Activity in Neuroblastoma NB2a Cells.
abstract: In this work, we have found that casein kinase II (CKII) phosphorylates the CacyBP/SIP protein under in vitro conditions and have mapped the phosphorylation site to threonine 184. Moreover, we present evidence that S100A6, a CacyBP/SIP interacting protein, inhibits this phosphorylation in the presence of Ca(2+). CacyBP/SIP phosphorylation by CKII was also observed in neuroblastoma NB2a cells. Interestingly, we have found that the effect of DRB, a CKII inhibitor, on CacyBP/SIP phosphorylation state is similar to that of S100A6 overexpression. Phosphorylation at threonine 184 seems to have an effect on CacyBP/SIP phosphatase activity since the T184E phosphorylation mimic mutant overexpressed in NB2a cells has lower phosphatase activity toward p-ERK1/2 when compared to the non-phosphorylable T184A mutant or to the wild-type protein. In conclusion, our data suggest that S100A6 and Ca(2+), through inhibiting CacyBP/SIP phosphorylation on threonine 184, are important regulators of CacyBP/SIP phosphatase activity and of ERK1/2-Elk-1 signaling pathway.
authors.affiliation: Nencki Institute of Experimental Biology, Warsaw, Poland.
authors.forename: Urszula
authors.initials: U
authors.lastname: Wasik
authors.affiliation: Nencki Institute of Experimental Biology, Warsaw, Poland.
authors.forename: Beata
authors.initials: B
authors.lastname: Kadziolka
authors.affiliation: Nencki Institute of Experimental Biology, Warsaw, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Kilanczyk
authors.affiliation: Nencki Institute of Experimental Biology, Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Filipek
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D004004:Dichlororibofuranosylbenzimidazole / Q000494:pharmacology; D051379:Mice; D009447:Neuroblastoma / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects / Q000235:genetics; D000075383:S100 Calcium Binding Protein A6; D009418:S100 Proteins / Q000235:genetics / Q000378:metabolism*; D050807:ets-Domain Protein Elk-1 / Q000378:metabolism*
chemical_list: C111922:Cacybp protein, mouse; D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D000075383:S100 Calcium Binding Protein A6; D009418:S100 Proteins; C489134:S100a6 protein, mouse; D050807:ets-Domain Protein Elk-1; D004004:Dichlororibofuranosylbenzimidazole
keywords: CASEIN KINASE II; CacyBP/SIP; ERK1/2; Elk-1; NB2a CELLS; S100A6