Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study describes the properties of a clone of immortalized cells (m-ICc12 cells) derived from the bases of small intestinal villi from 20-day-old fetuses of L-type pyruvate kinase (L-PK)/ TAg1 transgenic mice. The mice harbor the simian virus 40 large T antigen under the control of the 5' regulatory sequence from the L-PK gene. m-ICc12 cells expressed nuclear large T antigen, had a prolonged life span, and were nontumorigenic when injected into nude mice. They formed confluent monolayers of cuboid cells separated by tight junctions, developed dense, short apical microvilli, and formed domes. They also possessed cytokeratins, villin, aminopeptidase N, dipeptidyl-peptidase IV, and glucoamylase and retained crypt cell features, including intracellular sucrase isomaltase and alpha-L-fucose glycoconjugates accumulation and expression of the polymeric immunoglobulin receptor and the cystic fibrosis transmembrane conductance regulator gene. Thus the m-ICc12 cell line obtained by targeted oncogenesis in transgenic mice maintained in culture several important properties and differentiated functions of intestinal crypt cells.
 ...
PMID:Transimmortalized mouse intestinal cells (m-ICc12) that maintain a crypt phenotype. 876 49

Previous results from our laboratory have indicated a requirement for CK intermediate filaments (IF) for the organization of the apical domain in polarized epithelial cells in culture. The results seemed to be challenged by the phenotype of cytokeratin (CK) 8-deficient mice, which comprises only colorectal hyperplasia, female sterility and a weaker hepatocyte integrity. In this work localization with anti-CK antibodies indicated that many Ck8-/- epithelia still form IF in CK8-deficient mice, perhaps because of the expression of the promiscuous CK7. In the small intestine, only villus enterocytes lacked IFs. These cells appeared to lose syntaxin 3, and three apical membrane proteins (alkaline phosphatase, sucrase isomaltase and cystic fibrosis transmembrane conductance regulator) as they progressed along the villus. At the distal third of the villi, gamma-tubulin was found scattered within the cytoplasm of enterocytes, in contrast to its normal sub-apical localization, and the microtubules were disorganized. These results could not be attributed to increased numbers of apoptotic or necrotic cells. The only other cell type we found without IFs in CK8 null mice, the hepatocyte, displayed increased basolateral levels of one apical marker (HA4), indicating a correlation between the lack of intermediate filaments and an apical domain phenotype. These data suggest a novel function for intermediate filaments organizing the apical pole of simple polarized epithelial cells.
 ...
PMID:Anomalous apical plasma membrane phenotype in CK8-deficient mice indicates a novel role for intermediate filaments in the polarization of simple epithelia. 1117 25

The CFTR High Expresser (CHE) cells express eightfold higher levels of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel compared with neighboring enterocytes and were first identified by our laboratory (Ameen et al., Gastroenterology 108: 1016, 1995). We used double-label immunofluorescence microscopy to further study these enigmatic epithelial cells in rat intestine in vivo or ex vivo. CHE cells were found in duodenum, most frequent in proximal jejunum, and absent in ileum and colon. CFTR abundance increased in CHE cells along the crypt-villus axis. The basolateral Na(+)K(+)Cl(-) cotransporter NKCC1, a key transporter involved in Cl(-) secretion, was detected at similar levels in CHE cells and neighboring enterocytes at steady state. Microvilli appeared shorter in CHE cells, with low levels of Myosin 1a, a villus enterocyte-specific motor that retains sucrase/isomaltase in the brush-border membrane (BBM). CHE cells lacked alkaline phosphatase and absorptive villus enterocyte BBM proteins, including Na(+)H(+) exchanger NHE3, Cl(-)/HCO3(-) exchanger SLC26A6 (putative anion exchanger 1), and sucrase/isomaltase. High levels of the vacuolar-ATPase proton pump were observed in the apical domain of CHE cells. Levels of the NHE regulatory factor NHERF1, Na-K-ATPase, and Syntaxin 3 were similar to that of neighboring enterocytes. cAMP or acetylcholine stimulation robustly increased apical CFTR and basolateral NKCC1 disproportionately in CHE cells relative to neighboring enterocytes. These data strongly argue for a specialized role of CHE cells in Cl(-)-mediated "high-volume" fluid secretion on the villi of the proximal small intestine.
 ...
PMID:Characterization of CFTR High Expresser cells in the intestine. 2386 8