Calcium regulation of Ndr protein kinase mediated by S100 calcium-binding proteins.
Ndr is a nuclear serine/threonine protein kinase that belongs to a subfamily of kinases identified as being critical for the regulation of cell division and cell morphology. The regulatory mechanisms that control Ndr activity have not been characterized previously. In this paper, we present evidence that Ndr is regulated by EF-hand calcium-binding proteins of the S100 family, in response to changes in the intracellular calcium concentration. In vitro, S100B binds directly to and activates Ndr in a Ca2+-dependent manner. Moreover, Ndr is recovered from cell lysates in anti-S100B immunoprecipitates. The region of Ndr responsible for interaction with Ca2+/S100B is a basic/hydrophobic motif within the N-terminal regulatory domain of Ndr, and activation of Ndr by Ca2+/S100B is inhibited by a synthetic peptide derived from this region. In cultured cells, Ndr is rapidly activated following treatment with Ca2+ ionophore, and this activation is dependent upon the identified Ca2+/S100B-binding domain. Finally, Ndr activity is inhibited by W-7 in melanoma cells overexpressing S100B, but is unaffected by W-7 in melanoma cells that lack S100B. These results suggest that Ndr is regulated at least in part by changes in the intracellular calcium concentration, through binding of S100 proteins to its N-terminal regulatory domain.
Friedrich Miescher-Institut, Maulbeerstrasse 66, CH-4058 Basel.
T A
TA
Millward
C W
CW
Heizmann
B W
BW
Schäfer
B A
BA
Hemmings
D000818:Animals; D019556:COS Cells; D002118:Calcium / Q000502:physiology*; D020013:Calcium Signaling / Q000502:physiology; D002135:Calcium-Binding Proteins / Q000502:physiology*; D002467:Cell Nucleus / Q000201:enzymology; D002478:Cells, Cultured; D004789:Enzyme Activation; D006801:Humans; D009414:Nerve Growth Factors / Q000502:physiology*; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins
D002135:Calcium-Binding Proteins; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579160:S100B protein, human; D017346:Protein Serine-Threonine Kinases; D002118:Calcium