Cellular Communication and Signaling

Abstract

Cellular communication is a fundamental process by which cells perceive and respond to their environment, ensuring the coordination of biological functions essential to maintaining homeostasis. This intercellular dialogue is based on the exchange of chemical, electrical, or mechanical signals, which can act locally (juxtacrine or paracrine communication) or remotely (endocrine or synaptic communication). Cell signaling mechanisms typically begin with the reception of an extracellular signal via a specific receptor located on the surface or within the target cell. This interaction activates a signal transduction cascade, often composed of protein kinases, second messengers (cAMP, Ca²⁺, IP3), and transcription factors. These cascades amplify the initial signal and lead to specific biological responses : activation or repression of genes, proliferation, differentiation, migration, or apoptosis. Key signaling pathways include G protein-coupled receptor (GPCR), receptor tyrosine kinase (RTK), JAK/STAT, Wnt/β-catenin, and nuclear receptor pathways. Each of these pathways is finely regulated and can interact with other pathways (crosstalk), giving the cell a high degree of response plasticity. Dysfunction in cell signaling is implicated in many human pathologies, including cancers, autoimmune, neurodegenerative, and metabolic diseases. Current research is exploring new therapeutic targets within these signaling pathways, with the goal of modulating cellular messages specifically and efficiently. Signaling biomarkers are also used in diagnosis and prognosis to assess the pathophysiological state of tissues.