Progress in ciliary ion channel physiology

Abstract

Mammalian cilia are ubiquitous appendages found on the apical surface of cells. Primary and motile cilia are distinct in both morphology and function. Most cells have a solitary primary cilium (9+0), which lacks the central microtubule doublet characteristic of motile cilia (9+2). The immotile primary cilia house unique signaling components and sequester several important transcription factors. In contrast, motile cilia commonly extend into the lumen of respiratory airways, fallopian tubes, and brain ventricles to move their contents and/or produce gradients. In this review, we focus on the composition of putative ion channels found in both types of cilia and in the periciliary membrane and discuss their proposed functions. Our discussion does not cover specialized cilia in photoreceptor or olfactory cells, which express many more ion channels.

Protease‐activated receptor 2 activates airway apical membrane chloride permeability and increases ciliary beating

“…However, it is not yet fully clear how [Ca 2+ ] i during strong (100 mM) histamine stimulation reaches a level that can activate fluid secretion (30), because apical Ca 2+ -activated Cl 2 channels would be expected to be above the apical mitochondrial buffer (43) without detectably elevating the CBF. Further diffusional barriers into the cilia may have an important role (57), or other messengers activated by histamine (e.g., PKC) may blunt the effects of Ca 2+ on the CBF. Further studies of airway cell Ca 2+ signal localization, including better methods to study localized [Ca 2+ ] i directly within motile airway cell cilia, would explain those observations.…”

Evolutionary Cell Biology of Proteins from Protists to Humans and Plants

“…; Pablo et al. ). Also polycystin‐type channels are no more considered important for ciliary activity in animal cells—aside from the passive movement of the primary cilium (Battle et al.…”

“…TRP channels can form homo‐ or heteromeric channel complexes with variable channel properties including variable Ca 2+ selectivity (Pablo et al. ). In the primary cilium, they can encompass, for example, TRPPs type PKD2, PKD2‐1, TRPM4, and TRPV4 which are localized in the ciliary membrane (Pablo et al.…”

“…In the primary cilium, they can encompass, for example, TRPPs type PKD2, PKD2‐1, TRPM4, and TRPV4 which are localized in the ciliary membrane (Pablo et al. ; Phua et al. ).…”

“…In epithelial cells, TRPCs seem to occur, in part, in the ciliary and nonciliary cell membrane (Pablo et al. ). In cilia of the trachea, TRPV4 occurs, and PKD1 and PDK2 are also components of these motile cilia (Doerner et al.…”