Proteomic Analysis of TRPC Channels

Excerpt

Ca²⁺ is a ubiquitous and fundamental signaling component that is utilized by cells to regulate a diverse range of critical cellular functions. Typically, cells respond to a Ca²⁺ signal that is generated inside the cell in response to activation of a wide variety of cell surface receptors, including those involved in neurotransmitter, hormonal, and sensory signaling. In most cases, the initial Ca²⁺ signal generated in the cell is a specific increase in cytoplasmic [Ca²⁺] ([Ca²⁺]_i) resulting from release of Ca²⁺ from internal Ca²⁺ stores (mainly the endoplasmic reticulum [ER]) or entry of Ca²⁺ from the external medium across the plasma membrane. Both routes involve movement of Ca²⁺ through Ca²⁺ channels that are localized within these cellular membranes. While intracellular Ca²⁺ release from ER occurs via channels activated by inositol 1,4,5-trisphosphate (IP₃), cyclic ADP-ribose, or Ca²⁺ itself, Ca²⁺ influx across the plasma membrane is achieved via numerous types of Ca²⁺ channels, including voltage-gated Ca²⁺ channels and store-operated Ca²⁺ channels, as well as a variety of ligand-gated cation channels, although the type of channels can vary depending on the cell type.^–Among these, the transient receptor potential (TRP) superfamily of ion channels have been described to be involved in a diverse array of signaling mechanisms that regulate critical sensory functions in cells as well as other processes such as secretion, proliferation, neuronal guidance, cell death, and development.