Feedback inhibitor of fibroblast growth factor mediated Ras-MAPK signaling and ERK activation. May inhibit FGF-induced FGFR1 tyrosine phosphorylation. Regulates the nuclear ERK signaling pathway by spatially blocking nuclear translocation of activated ERK without inhibiting cytoplasmic phosphorylation of ERK. Mediates JNK activation and may be involved in apoptosis.
Expressed in umbilical vein endothelial cells and in several highly vascularized tissues such as kidney, colon, skeletal muscle, heart and small intestine. Highly expressed in ductal epithelial cells of salivary glands, seminal vesicles and the collecting tubules of the kidney. Isoform 1 is also highly expressed in both fetal and adult brain, pituarity, tonsils, spleen, adenoids, fetal kidney, liver, testes and ovary. Isoform 1 is also expressed at moderate levels in primary aortic endothelial cells and adrenal medulla, and at low levels in adrenal cortex. Isoform 4 is specifically and highly expressed in pituitary, fetal brain and umbilical vein endothelial cells.
Cytoplasm and Golgi apparatus membrane. Cell membrane. Predominantly associated with the Golgi apparatus and is partially translocated to the plasma membrane upon stimulation.
Iwamoto N et al. Context-specific flow through the MEK/ERK module produces cell- and ligand-specific patterns of ERK single and double phosphorylation. Sci Signal9:ra13 (2016).
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