Involvement of cytoskeletal integrity in the regulation of Cl- and amylase secretion from rat parotid acinar cells

Abstract

The cytoskeleton serves as a signal modulator for Ca 2+ and cAMP-regulated cell functions including the secretion of ions and granule contents. The interaction between Ca 2+ and cAMP signaling systems potentiates amylase secretion and suppresses Cl − secretion in the parotid glands. In this study, we investigated the role of the cytoskeleton in the modulation of Cl − and amylase secretion from rat parotid acinar cells upon activation of each intracellular signaling system and their interaction. Cytochalasin D markedly inhibited the Ca 2+ -activated outwardly rectifying Cl − current at positive membrane potentials and carbachol (CCh)-induced Cl − currents in the whole-cell configuration at −80 mV, whereas colchicine enhanced Cl − currents. Cytochalasin D, but not colchicine, markedly inhibited CCh-induced Cl − secretion. Synergistic actions of CCh and forskolin on Cl − and amylase secretion were observed even in the presence of cytochalasin D. These results suggest that the synergistic effects of Ca 2+ and cAMP signaling systems on amylase and Cl − secretion do not require actin filament integrity but that secretion by the two signals themselves does require actin filament integrity.Actin and tubulin cytoskeletons are involved in the regulation of cell morphology and intracellular transport. They also affect the membrane permeability and secretory functions of glandular cells; cytoskeletal integrity modulates amylase secretion by β-adrenergic agonists (4,5,24,37) and cytoskeletal organization is related to the regulation of ion channels (1, 12), exchangers (16) and transporters (7) involved in the secretion of salivary fluid during cholinergic stimulation (22,27). Cytoskeletal integrity might regulate Cl −

Proteomic Analysis of Human Transplanted Submandibular Gland in Patients with Epiphora after Transplantation

“…The polymerization and depolymerization of actin filaments generates direct forces that drive changes in cell shape and, together with molecular motors that move along the actin filaments and microtubules, guide the organization of cellular components . The disruption of microfilaments with cytochalasin B prevented amylase release in rat submandibular glands, which indicates that secretion of amylase depends on the integrity of microfilaments. , It has been reported that actin filament integrity was required for the activation of Cl − channels in rat parotid acinar cells . The optimal Na + /H + exchanger activity also requires the integrity of the cellular F-actin network in a hamster ovary cell line .…”

“…Of the cytoskeletal proteins, actin is a major structural element of cytoskeleton and is involved in saliva secretion. − Alpha-actinin-4 is an actin-binding protein and is present in the perinuclear region of cytoplasm and nucleus and colocalized with actin stress fibers . Vimentin, keratin and lamin-A/C are components of intermediate filaments.…”

TMEM16E (GDD1) Exhibits Protein Instability and Distinct Characteristics in Chloride Channel/Pore Forming Ability

“…The Tukey's test was used to compare group means of current amplitudes using Mathematica software (Wolfram Research, Champaign, IL). Details of the devices used in patch‐clamp recordings have been previously described (Kongo et al, ).…”

Autoantibodies in Sjögren’s syndrome patients acutely inhibit muscarinic receptor function

“…In epithelial cells, α‐fodrin reorganization is believed to play an important role in secretion (Perrin et al , 1987), as it has been shown to inhibit phospholipases C, A2, and D in permeabilized HL‐60 cells (Lukowski et al , 1998). Cytochalasin D, an actin‐depolymerizing agent, suppresses CCh‐induced Cl − currents and forskolin‐induced amylase secretion in rat parotid acinar cells, suggesting that cytoskeletal integrity is also involved in the regulation of salivary secretion (Kongo et al , 2008).…”

“…Stimulation of M3R increases the cytoplasmic‐free calcium concentration ([Ca 2+ ] i ), subsequently activating Ca 2+ ‐dependent K + and Cl − channels (Park et al , 2001; Melvin et al , 2005). Cytoskeletal integrity is also involved in the regulation of salivary secretion (Kongo et al , 2008). Stimulation of muscarinic receptors produces a reorganization of the α‐fodrin cytoskeleton in parotid acinar cells (Perrin et al , 1992).…”