PTBdomeenien

PTBdomeenien are a family of protein domains known as phosphotyrosine-binding (PTB) domains. They are found in a variety of signaling and cargo-adaptor proteins and function primarily to mediate protein–protein interactions by recognizing specific peptide motifs, often containing phosphorylated tyrosine residues.

Structure and binding characteristics

PTBdomeenien are typically small modules, about 100 to 120 amino acids in length, and adopt a beta-sandwich fold. Binding specificity is determined by the surrounding amino acid context of the target motif, allowing interactions with phosphorylated and, in some cases, non-phosphorylated sequences. The affinity and selectivity of a given PTBdomeen pair depend on both the domain itself and the partner peptide, making these domains versatile adapters in signaling complexes.

Biological roles

PTBdomeenien play key roles in signal transduction and intracellular trafficking. They often recruit effector proteins to activated receptors or endocytic cargo, thereby influencing receptor internalization, sorting, and downstream signaling cascades. In many systems, PTBdomeenien cooperate with other modular domains to build multi-protein assemblies that propagate or regulate cellular responses.

Distribution and examples

PTBdomeenien occur across a wide range of eukaryotes and are embedded in various multi-domain proteins, including adaptor proteins involved in receptor signaling and endocytosis. Notable examples include domains found in Dab1, Numb, and related adapters, which participate in pathways governing development and cellular communication.

Research and clinical relevance

Structural and biochemical studies have elucidated many PTBdomeenien structures and binding motifs, informing models of their role in cellular signaling. Misregulation of PTBdomeenien interactions has been linked to disease processes, including cancer and developmental disorders, highlighting their importance as mediators of precise cellular communication.

See also

SH2 domains, PDZ domains, PH domains, endocytosis, receptor signaling.