Abstract
Syx is a Rho-specific guanine nucleotide exchange factor (GEF) that localizes at cell-cell junctions and promotes junction stability by activating RhoA and the downstream effector Diaphanous homolog 1 (Dia1). Previously, we identified several molecules, including 14-3-3 proteins, as Syx-interacting partners. In the present study, we show that 14-3-3 isoforms interact with Syx at both its N- and C-terminal regions in a phosphorylation- dependent manner. We identify the protein kinase D-mediated phosphorylation of serine 92 on Syx, and additional phosphorylation at serine 938, as critical sites for 14-3-3 association. Our data indicate that the binding of 14-3-3 proteins inhibits the GEF activity of Syx. Furthermore, we show that phosphorylation-deficient, 14-3-3-uncoupled Syx exhibits increased junctional targeting and increased GEF activity, resulting in the strengthening of the circumferential junctional actin ring in Madin-Darby canine kidney cells. These findings reveal a novel means of regulating junctional Syx localization and function by phosphorylation-induced 14-3-3 binding and further support the importance of Syx function in maintaining stable cell-cell contacts.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 6640-6650 |
| Number of pages | 11 |
| Journal | Journal of Biological Chemistry |
| Volume | 288 |
| Issue number | 9 |
| DOIs | |
| State | Published - Mar 1 2013 |
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ASJC Scopus subject areas
- Biochemistry
- Cell Biology
- Molecular Biology
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Phosphorylation-mediated 14-3-3 protein binding regulates the function of the rho-specific guanine nucleotide exchange factor (RhoGEF) syx. / Ngok, Siu P.; Geyer, Rory; Kourtidis, Antonis; Storz, Peter; Anastasiadis, Panagiotis Z.
In: Journal of Biological Chemistry, Vol. 288, No. 9, 01.03.2013, p. 6640-6650.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Phosphorylation-mediated 14-3-3 protein binding regulates the function of the rho-specific guanine nucleotide exchange factor (RhoGEF) syx
AU - Ngok, Siu P.
AU - Geyer, Rory
AU - Kourtidis, Antonis
AU - Storz, Peter
AU - Anastasiadis, Panagiotis Z
PY - 2013/3/1
Y1 - 2013/3/1
N2 - Syx is a Rho-specific guanine nucleotide exchange factor (GEF) that localizes at cell-cell junctions and promotes junction stability by activating RhoA and the downstream effector Diaphanous homolog 1 (Dia1). Previously, we identified several molecules, including 14-3-3 proteins, as Syx-interacting partners. In the present study, we show that 14-3-3 isoforms interact with Syx at both its N- and C-terminal regions in a phosphorylation- dependent manner. We identify the protein kinase D-mediated phosphorylation of serine 92 on Syx, and additional phosphorylation at serine 938, as critical sites for 14-3-3 association. Our data indicate that the binding of 14-3-3 proteins inhibits the GEF activity of Syx. Furthermore, we show that phosphorylation-deficient, 14-3-3-uncoupled Syx exhibits increased junctional targeting and increased GEF activity, resulting in the strengthening of the circumferential junctional actin ring in Madin-Darby canine kidney cells. These findings reveal a novel means of regulating junctional Syx localization and function by phosphorylation-induced 14-3-3 binding and further support the importance of Syx function in maintaining stable cell-cell contacts.
AB - Syx is a Rho-specific guanine nucleotide exchange factor (GEF) that localizes at cell-cell junctions and promotes junction stability by activating RhoA and the downstream effector Diaphanous homolog 1 (Dia1). Previously, we identified several molecules, including 14-3-3 proteins, as Syx-interacting partners. In the present study, we show that 14-3-3 isoforms interact with Syx at both its N- and C-terminal regions in a phosphorylation- dependent manner. We identify the protein kinase D-mediated phosphorylation of serine 92 on Syx, and additional phosphorylation at serine 938, as critical sites for 14-3-3 association. Our data indicate that the binding of 14-3-3 proteins inhibits the GEF activity of Syx. Furthermore, we show that phosphorylation-deficient, 14-3-3-uncoupled Syx exhibits increased junctional targeting and increased GEF activity, resulting in the strengthening of the circumferential junctional actin ring in Madin-Darby canine kidney cells. These findings reveal a novel means of regulating junctional Syx localization and function by phosphorylation-induced 14-3-3 binding and further support the importance of Syx function in maintaining stable cell-cell contacts.
UR - http://www.scopus.com/inward/record.url?scp=84874789491&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84874789491&partnerID=8YFLogxK
U2 - 10.1074/jbc.M112.432682
DO - 10.1074/jbc.M112.432682
M3 - Article
C2 - 23335514
AN - SCOPUS:84874789491
VL - 288
SP - 6640
EP - 6650
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 9
ER -