Boonstra J, Rijken P, Humbel B, Cremers F, Verkleij A, van Bergen en Henegouwen P
Dept. Molecular Cell Biology, University Utrecht, The Netherlands.
Cell Biol Int. 1995 May;19(5):413-30. doi: 10.1006/cbir.1995.1086.
Epidermal growth factor (EGF) is a single polypeptide of 53 amino acid residues which is involved in the regulation of cell proliferation. Egf exerts its effects in the target cells by binding to the plasma membrane located EGF receptor. The EGF receptor is a transmembrane protein tyrosine kinase. Binding of EGF to the receptor causes activation of the kinase and subsequently receptor autophosphorylation. The autophosphorylation is essential for the interaction of the receptor with its substrates. These bind to the receptor by the so-called SH2 domains. The signal transduction pathways activated by EGF include the phosphatidylinositol pathway, leading to activation of protein kinase C and to increase in the intracellular Ca2+ concentration, and to the ras pathway leading to MAP kinase activation. Recently the cytoplasm has been implicated as playing an important role in EGF induced signal transduction. The EGF receptor has been demonstrated to be an actin-binding protein. In addition EGF causes a rapid actin depolymerisation and the formation of membrane ruffles. In particular these membrane ruffles have been shown to act as the first site of signal transduction after EGF binding, and thus may be considered as signal transduction structures. Finally evidence has been presented suggesting a positive role for EGF and/or the receptor in the nucleus.
表皮生长因子（EGF）是一种由53个氨基酸残基组成的单链多肽，参与细胞增殖的调控。EGF通过与位于质膜上的EGF受体结合，在靶细胞中发挥作用。EGF受体是一种跨膜蛋白酪氨酸激酶。EGF与受体的结合会导致激酶的激活，随后受体发生自身磷酸化。自身磷酸化对于受体与其底物的相互作用至关重要。这些底物通过所谓的SH2结构域与受体结合。由EGF激活的信号转导途径包括磷脂酰肌醇途径，导致蛋白激酶C的激活和细胞内Ca2+浓度的增加，以及导致MAP激酶激活的ras途径。最近，细胞质被认为在EGF诱导的信号转导中起重要作用。EGF受体已被证明是一种肌动蛋白结合蛋白。此外，EGF会导致肌动蛋白迅速解聚并形成膜皱褶。特别是这些膜皱褶已被证明是EGF结合后信号转导的第一个位点，因此可被视为信号转导结构。最后，有证据表明EGF和/或受体在细胞核中起积极作用。
