Gqproteiineihin

Gqproteiineihin, or Gq proteins in English, are a class of guanine nucleotide-binding proteins that act as signal transducers. They are a type of heterotrimeric G protein, meaning they consist of three subunits: alpha (α), beta (β), and gamma (γ). The Gq family specifically refers to the Gα subunits that are activated by certain cell surface receptors, known as G protein-coupled receptors (GPCRs).

Upon activation of their cognate GPCR by an extracellular signal, such as a hormone or neurotransmitter, the Gq protein undergoes a conformational change. This change leads to the exchange of guanosine diphosphate (GDP) bound to the Gα subunit for guanosine triphosphate (GTP). The activated Gα subunit then dissociates from the βγ dimer and interacts with downstream effector proteins.

The primary effector pathway activated by Gq proteins is the phospholipase C (PLC) pathway. Activated Gαq stimulates PLC, which cleaves phosphatidylinositol 4,5-bisphosphate (PIP2) into two second messengers: inositol trisphosphate (IP3) and diacylglycerol (DAG). IP3 triggers the release of calcium ions from intracellular stores, leading to a rise in intracellular calcium concentration. DAG, along with the elevated calcium, activates protein kinase C (PKC), which phosphorylates various target proteins, thereby modulating cellular functions.

Gq proteins are involved in a wide range of physiological processes, including vision, olfaction, taste, smooth muscle contraction, and inflammatory responses. Dysregulation of Gq signaling pathways has been implicated in various diseases, making them important targets for drug development.