Regulation of Kv Channel Activity and Intercellular Junctions by Polyamines in Intestinal Epithelial Cells

2006 ◽  
pp. 363-382 ◽  
Author(s):  
Jaladanki N. Rao ◽  
Jian-Ying Wang
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Intercellular Junctions ◽  
Intestinal Epithelial ◽  
Channel Activity ◽  
Kv Channel

Identification of a Basolateral Membrane Potassium Channel from Teleost Intestinal Epithelial Cells

1991 ◽  
Vol 159 (1) ◽  
pp. 45-64
Author(s):  
CHRISTOPHER A. LORETZ ◽  
CHARLES R. FOURTNER
Keyword(s):  
Membrane Potential ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Basolateral Membrane ◽  
K Channel ◽  
Ca Channel ◽  
Intestinal Epithelial ◽  
Channel Activity ◽  
Open Probability ◽  
Physiological Range

Using patch-clamp techniques, a Ca2+-dependent, voltage-gated K+ channel [K(Ca) channel] was isolated from the basolateral membrane of NaCl-absorbing intestinal epithelial cells of the goby Gillichthys mirabilis. This K(Ca) channel had a high conductance (approximately 150 pS) in the physiological range of membrane potential. Conclusive identification as a K+ channel is supported by dependence of the reversal potential for single-channel current on the K+ concentration gradient and the ability of Ba2+, Cs+ and other pharmacological agents to block the channel. The channel was highly selective for K+ over Na+ (PNa/PK=0.04). Channel activity, expressed as open probability (Po), was dependent on membrane potential with depolarization increasing Po over the physiological range in the presence of Ca2+. Channel activity was also dependent on cytoplasmic-side Ca2+. Po was reduced to near-zero levels following EGTA chelation of Ca2+ in the solution bathing the cytoplasmic face of excised membrane patches; channel activity was most sensitive to changes in Ca2+ concentration between 10nmoll−1 and 10μmoll−1. This K(Ca) channel may be one of several avenues for K+ exit across the basolateral cell membrane and, as such, may play roles in both transepithelial salt transport and maintenance of intracellular ionic composition.

scholarly journals Colitis is associated with loss of LHPP and up-regulation of histidine phosphorylation in intestinal epithelial cells

2020 ◽  
Author(s):  
Markus Linder ◽  
Dritan Liko ◽  
Venkatesh Kancherla ◽  
Salvatore Piscuoglio ◽  
Michael N. Hall
Keyword(s):  
Epithelial Cells ◽  
Posttranslational Modification ◽  
Intestinal Inflammation ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Channel Activity ◽  
Physiological Conditions ◽  
Inflammatory Bowel ◽  
Histidine Phosphorylation ◽  
Cycle Regulation

AbstractProtein histidine phosphorylation (pHis) is a posttranslational modification involved in cell cycle regulation, ion channel activity and phagocytosis (1). Using novel monoclonal antibodies to detect pHis (2), we recently reported that loss of the histidine phosphatase LHPP results in elevated pHis levels in hepatocellular carcinoma (3). Here, we show that intestinal inflammation correlates with loss of LHPP, in DSS-treated mice and in inflammatory bowel disease (IBD) patients. Increased histidine phosphorylation was observed in intestinal epithelial cells (IECs), as determined by pHis immunofluorescence staining of colon samples from a colitis mouse model. However, ablation of Lhpp did not cause increased pHis or promote intestinal inflammation in physiological conditions or after DSS treatment. Our observations suggest that increased histidine phosphorylation plays a role in colitis, but loss of LHPP is not sufficient to increase pHis or to cause inflammation in the intestine.

Anorexic effect of K+ channel blockade in mesenteric arterial smooth muscle and intestinal epithelial cells

2001 ◽  
Vol 91 (5) ◽  
pp. 2322-2333 ◽  
Author(s):  
Sharon S. McDaniel ◽  
Oleksandr Platoshyn ◽  
Ying Yu ◽  
Michele Sweeney ◽  
Victor A. Miriel ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Weight Gain ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Membrane Depolarization ◽  
Intestinal Epithelial ◽  
Whole Cell ◽  
Kv Channel ◽  
Kv Channels ◽  
Α And Β Subunits

Activity of voltage-gated K+ (Kv) channels controls membrane potential ( E m). Membrane depolarization due to blockade of K+ channels in mesenteric artery smooth muscle cells (MASMC) should increase cytoplasmic free Ca2+ concentration ([Ca2+]cyt) and cause vasoconstriction, which may subsequently reduce the mesenteric blood flow and inhibit the transportation of absorbed nutrients to the liver and adipose tissue. In this study, we characterized and compared the electrophysiological properties and molecular identities of Kv channels and examined the role of Kv channel function in regulating E m in MASMC and intestinal epithelial cells (IEC). MASMC and IEC functionally expressed multiple Kv channel α- and β-subunits (Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv1.5, Kv2.1, Kv4.3, and Kv9.3, as well as Kvβ1.1, Kvβ2.1, and Kvβ3), but only MASMC expressed voltage-dependent Ca2+ channels. The current density and the activation and inactivation kinetics of whole cell Kv currents were similar in MASMC and IEC. Extracellular application of 4-aminopyridine (4-AP), a Kv-channel blocker, reduced whole cell Kv currents and caused E m depolarization in both MASMC and IEC. The 4-AP-induced E m depolarization increased [Ca2+]cyt in MASMC and caused mesenteric vasoconstriction. Furthermore, ingestion of 4-AP significantly reduced the weight gain in rats. These results suggest that MASMC and IEC express multiple Kv channel α- and β-subunits. The function of these Kv channels plays an important role in controlling E m. The membrane depolarization-mediated increase in [Ca2+]cyt in MASMC and mesenteric vasoconstriction may inhibit transportation of absorbed nutrients via mesenteric circulation and limit weight gain.

Activation of K+ channels and increased migration of differentiated intestinal epithelial cells after wounding

2002 ◽  
Vol 282 (4) ◽  
pp. C885-C898 ◽  
Author(s):  
Jaladanki N. Rao ◽  
Oleksandr Platoshyn ◽  
Li Li ◽  
Xin Guo ◽  
Vera A. Golovina ◽  
...  
Keyword(s):  
Cell Migration ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Fiber Formation ◽  
Intestinal Epithelial ◽  
Membrane Hyperpolarization ◽  
Kv Channel ◽  
Kv Channels ◽  
Channel Expression

Early mucosal restitution occurs by epithelial cell migration to reseal superficial wounds after injury. Differentiated intestinal epithelial cells induced by forced expression of the Cdx2 gene migrate over the wounded edge much faster than undifferentiated parental cells in an in vitro model. This study determined whether these differentiated intestinal epithelial cells exhibit increased migration by altering voltage-gated K+ (Kv) channel expression and cytosolic free Ca2+ concentration ([Ca2+]cyt). Stable Cdx2-transfected IEC-6 cells (IEC-Cdx2L1) with highly differentiated phenotype expressed higher basal levels of Kv1.1 and Kv1.5 mRNAs and proteins than parental IEC-6 cells. Neither IEC-Cdx2L1 cells nor parental IEC-6 cells expressed voltage-dependent Ca2+ channels. The increased expression of Kv channels in differentiated IEC-Cdx2L1 cells was associated with an increase in whole cell K+ currents, membrane hyperpolarization, and a rise in [Ca2+]cyt. The migration rates in differentiated IEC-Cdx2L1 cells were about four times those of parental IEC-6 cells. Inhibition of Kv channel expression by polyamine depletion decreased [Ca2+]cyt, reduced myosin stress fibers, and inhibited cell migration. Elevation of [Ca2+]cyt by ionomycin promoted myosin II stress fiber formation and increased cell migration. These results suggest that increased migration of differentiated intestinal epithelial cells is mediated, at least partially, by increasing Kv channel activity and Ca2+ influx during restitution.

Three-dimensional organization and functional relationships of endocytotic compartments in pig intestinal epithelial cells

1992 ◽  
Vol 50 (1) ◽  
pp. 576-577
Author(s):  
Julian P. Heath ◽  
Buford L. Nichols ◽  
László G. Kömüves
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Three Dimensional ◽  
Intestinal Epithelial ◽  
Cell Surfaces ◽  
Basal Surface ◽  
Functional Relationships

The newborn pig intestine is adapted for the rapid and efficient absorption of nutrients from colostrum. In enterocytes, colostral proteins are taken up into an apical endocytotic complex of channels that transports them to target organelles or to the basal surface for release into the circulation. The apical endocytotic complex of tubules and vesicles clearly is a major intersection in the routes taken by vesicles trafficking to and from the Golgi, lysosomes, and the apical and basolateral cell surfaces.Jejunal tissues were taken from piglets suckled for up to 6 hours and prepared for electron microscopy and immunocytochemistry as previously described.

Human and mouse intestinal epithelial cells (IEC) present glycolipid antigens to natural killer (NK)-T cells in a CD1d-restricted manner

2001 ◽  
Vol 120 (5) ◽  
pp. A37-A37
Author(s):  
Y VANDEWAL ◽  
R PITMAN ◽  
R HERSHBERG ◽  
S COLGAN ◽  
S BEHAR ◽  
...  
Keyword(s):  
T Cells ◽  
Epithelial Cells ◽  
Natural Killer ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Nk T Cells ◽  
Human And Mouse

Thrombin enhances migration of intestinal epithelial cells

2001 ◽  
Vol 120 (5) ◽  
pp. A504-A504
Author(s):  
A NEUMANN ◽  
M DEPKAPRONDZINSKI ◽  
C WILHELM ◽  
K FELGENHAUER ◽  
T CASPRITZ ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial
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