TY - JOUR
T1 - ERK1/2 associates with the c-Met-binding domain of growth factor receptor-bound protein 2 (Grb2)-associated binder-1 (Gab1)
T2 - Role in ERK1/2 and early growth response factor-1 (Egr-1) nuclear accumulation
AU - Osawa, Masaki
AU - Itoh, Seigo
AU - Ohta, Shinsuke
AU - Huang, Qunhua
AU - Berk, Bradford C.
AU - Marmarosh, Nicole Lerner
AU - Che, Wenyi
AU - Ding, Bo
AU - Yan, Chen
AU - Abe, Jun Ichi
PY - 2004/7/9
Y1 - 2004/7/9
N2 - Endothelial cell (EC) migration contributes to reendothelialization after angioplasty of rupture of atherosclerotic plaques. Extracellular signal-regulated kinase (ERK)1/2 translocates to the nucleus and activates transcription factors such as Ets-like transcription factor-1 and early growth response factor-1 (Egr-1) during reendothelialization. Because ERK1/2 does not possess a nuclear localization signal (NLS), its mechanism of translocation and accumulation in the nucleus remains unclear. Because Gab1 has a putative NLS in its N-terminal region, and Gab1 associates with phosphorylated ERK1/2, we hypothesized that Gab1 participates in ERK1/2 and Egr-1 nuclear accumulation. Using regenerating EC as a model system, we found that endogenous growth factor receptor-bound protein 2-associated binder-1 (Gab1) translocates into the nucleus in migrating EC. Wild-type red fluorescent protein-tagged Gab1 could be observed in both nucleus and cytoplasm, whereas the putative NLS deletion mutant (ΔNLS-Gab1) specifically localized in the cytoplasm. In addition, reduction of Gab1 expression by antisense Gab1 oligos or overexpression of ΔNLS-Gab1 inhibited serum-induced ERK1/2 and Egr-1 nuclear accumulation, suggesting a functional role for the NLS of Gab1 and a role for Gab1-ERK1/2 interactions in ERK1/2-Egr-1 nuclear accumulation. To investigate whether Gab1-ERK1/2 interaction is critical for ERK1/2 and Egr-1 nuclear accumulation, we created a dominant-negative Gab1 construct that consisted of the c-Met binding domain (amino acids 442-536) of Gab1. We found that overexpression of the c-Met binding domain of Gab1 disrupted serum-induced Gab1-ERK1 interaction and inhibited ERK1 and Egr-1 nuclear accumulation. These data suggest that Gab1-ERK1/2 binding and their nuclear translocation play a crucial role in Egr-1 nuclear accumulation.
AB - Endothelial cell (EC) migration contributes to reendothelialization after angioplasty of rupture of atherosclerotic plaques. Extracellular signal-regulated kinase (ERK)1/2 translocates to the nucleus and activates transcription factors such as Ets-like transcription factor-1 and early growth response factor-1 (Egr-1) during reendothelialization. Because ERK1/2 does not possess a nuclear localization signal (NLS), its mechanism of translocation and accumulation in the nucleus remains unclear. Because Gab1 has a putative NLS in its N-terminal region, and Gab1 associates with phosphorylated ERK1/2, we hypothesized that Gab1 participates in ERK1/2 and Egr-1 nuclear accumulation. Using regenerating EC as a model system, we found that endogenous growth factor receptor-bound protein 2-associated binder-1 (Gab1) translocates into the nucleus in migrating EC. Wild-type red fluorescent protein-tagged Gab1 could be observed in both nucleus and cytoplasm, whereas the putative NLS deletion mutant (ΔNLS-Gab1) specifically localized in the cytoplasm. In addition, reduction of Gab1 expression by antisense Gab1 oligos or overexpression of ΔNLS-Gab1 inhibited serum-induced ERK1/2 and Egr-1 nuclear accumulation, suggesting a functional role for the NLS of Gab1 and a role for Gab1-ERK1/2 interactions in ERK1/2-Egr-1 nuclear accumulation. To investigate whether Gab1-ERK1/2 interaction is critical for ERK1/2 and Egr-1 nuclear accumulation, we created a dominant-negative Gab1 construct that consisted of the c-Met binding domain (amino acids 442-536) of Gab1. We found that overexpression of the c-Met binding domain of Gab1 disrupted serum-induced Gab1-ERK1 interaction and inhibited ERK1 and Egr-1 nuclear accumulation. These data suggest that Gab1-ERK1/2 binding and their nuclear translocation play a crucial role in Egr-1 nuclear accumulation.
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U2 - 10.1074/jbc.M309371200
DO - 10.1074/jbc.M309371200
M3 - Article
C2 - 15078886
AN - SCOPUS:3142723480
SN - 0021-9258
VL - 279
SP - 29691
EP - 29699
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 28
ER -