Signalwegen

Signalwegen refer to the interconnected signaling pathways that convey information from a cell's environment to its interior, thereby regulating cellular processes such as growth, differentiation, metabolism and survival. They comprise receptors, transducers, second messengers, and effectors that form cascades of molecular interactions.

Receptors detect stimuli and initiate signaling, through membrane-bound receptors like receptor tyrosine kinases and G protein-coupled receptors, or intracellular receptors for lipophilic signals. The signal is transduced by proteins such as G proteins, kinases and phosphatases, often amplified through cascades. Second messengers such as cyclic AMP, Ca2+ and IP3 propagate and modulate the response, which is ultimately executed by transcription factors and metabolic enzymes.

Major signalwegen families include receptor tyrosine kinases (EGFR, VEGFR), GPCRs, JAK-STAT cytokine receptors, and pathways like MAPK/ERK, PI3K-Akt, PLC, Notch, Wnt and Hedgehog. These systems exhibit specificity and temporal dynamics, with cross-talk and feedback shaping outcomes.

Regulation of signalwegen is complex, involving scaffolding proteins, compartmentalization, and feedback loops that control intensity and duration. Dysregulation can contribute to diseases such as cancer, metabolic disorders and neurodegeneration, making signal transduction a focus for therapeutic intervention.

In research, signalwegen are studied with molecular biology techniques, single-cell analyses, and computational models to map networks and predict responses. Therapeutic strategies target components of signaling pathways to modulate disease processes.