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Pleckstrin homology (PH) domain of Downstream of tyrosine kinase 1, 2, and 3 The Dok family adapters are phosphorylated by different protein tyrosine kinases. Dok proteins are involved in processes such as modulation of cell differentiation and proliferation, as well as in control of the cell spreading and migration The Dok protein contains an N-terminal pleckstrin homology (PH) domain followed by a central phosphotyrosine binding (PTB) domain, which has a PH-like fold, and a proline- and tyrosine-rich C-terminal tail. The PH domain is binds to acidic phospholids and localizes proteins to the plasma membrane. There are 7 mammalian Dok members: Dok-1 to Dok-7. Dok-1 and Dok-2 act as negative regulators of the Ras-Erk pathway downstream of many immunoreceptor-mediated signaling systems, and it is believed that recruitment of p120 rasGAP by Dok-1 and Dok-2 is critical to their negative regulation. Dok-3 is a negative regulator of the activation of JNK and mobilization of Ca2+ in B-cell receptor-mediated signaling, interacting with SHIP-1 and Grb2. In general, PH domains have diverse functions, but are generally involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",