TY - JOUR
T1 - Protein kinase C μ is negatively regulated by 14-3-3 signal transduction proteins
AU - Hausser, Angelika
AU - Storz, Peter
AU - Link, Gisela
AU - Stoll, Hartmut
AU - Liu, Yun Cai
AU - Altman, Amnon
AU - Pfizenmaier, Klaus
AU - Johannes, Franz Josef
PY - 1999/4/2
Y1 - 1999/4/2
N2 - Recent studies have documented direct interaction between 14-3-3 proteins and key molecules in signal transduction pathways like Ras, Cbl, and protein kinases. In T cells, the 14-3-3τ isoform has been shown to associate with protein kinase C θ and to negatively regulate interleukin-2 secretion. Here we present data that 14-3-3τ interacts with protein kinase C μ (PKCμ), a subtype that differs from other PKC members in structure and activation mechanisms. Specific interaction of PKCμ and 14-3-3τ can be shown in the T cell line Jurkat by immunocoprecipitiation and by pulldown assays of either endogenous or overexpressed proteins using PKCμ-specific antibodies and GST-14-3-3 fusion proteins, respectively. Using PKCμ deletion mutants, the 14-3-3τ binding region is mapped within the regulatory C1 domain. Binding of 14-3-3τ to PKCμ is significantly enhanced upon phorbol ester stimulation of PKCμ kinase activity in Jurkat cells and occurs via a Cbl-like serine containing consensus motif. However, 14-3-3τ is not a substrate of PKCμ. In contrast 14-3-3τ strongly down-regulates PKCμ kinase activity in vitro. Moreover, overexpression of 14-3-3τ significantly reduced phorbol ester induced activation of PKCμ kinase activity in intact cells. We therefore conclude that 14-3-3τ is a negative regulator of PKCμ in T cells.
AB - Recent studies have documented direct interaction between 14-3-3 proteins and key molecules in signal transduction pathways like Ras, Cbl, and protein kinases. In T cells, the 14-3-3τ isoform has been shown to associate with protein kinase C θ and to negatively regulate interleukin-2 secretion. Here we present data that 14-3-3τ interacts with protein kinase C μ (PKCμ), a subtype that differs from other PKC members in structure and activation mechanisms. Specific interaction of PKCμ and 14-3-3τ can be shown in the T cell line Jurkat by immunocoprecipitiation and by pulldown assays of either endogenous or overexpressed proteins using PKCμ-specific antibodies and GST-14-3-3 fusion proteins, respectively. Using PKCμ deletion mutants, the 14-3-3τ binding region is mapped within the regulatory C1 domain. Binding of 14-3-3τ to PKCμ is significantly enhanced upon phorbol ester stimulation of PKCμ kinase activity in Jurkat cells and occurs via a Cbl-like serine containing consensus motif. However, 14-3-3τ is not a substrate of PKCμ. In contrast 14-3-3τ strongly down-regulates PKCμ kinase activity in vitro. Moreover, overexpression of 14-3-3τ significantly reduced phorbol ester induced activation of PKCμ kinase activity in intact cells. We therefore conclude that 14-3-3τ is a negative regulator of PKCμ in T cells.
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U2 - 10.1074/jbc.274.14.9258
DO - 10.1074/jbc.274.14.9258
M3 - Article
C2 - 10092600
AN - SCOPUS:0033515627
SN - 0021-9258
VL - 274
SP - 9258
EP - 9264
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 14
ER -