Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.27 (thermolysin)
 1,894 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

(Na,K)-ATPase is an integral membrane protein responsible for maintaining the Na+ and K+ ion concentration gradients across the plasma membranes of cells. All active (Na,K)-ATPase preparations consist of two subunits, designated alpha and beta. The alpha-subunit is the catalytic subunit and contains the cardiac glycoside binding site. In contrast, the physiological function of the beta-subunit remains unclear although it appears to be involved in the processes of folding, membrane insertion, and stabilization of the alpha-subunit. Previous work has determined the amino acid sequence and disulfide bond arrangements for the beta-subunit from both lamb and dog kidney. In this report, we describe the isolation and structural characterization of the glycan moieties of the beta-subunit from both lamb and dog kidney (Na,K)-ATPase. The three glycosylation sites of these beta-subunits were fractionated using reverse phase chromatography after cleavage of the polypeptide chain with trypsin and thermolysin. Glycopeptides derived from each glycosylation site were analyzed by matrix-assisted laser desorption ionization mass spectrometry. The mass spectrometry results indicated that the predominant glycoforms at the three glycosylation sites of these beta-subunits were a combination of the tetraantennary glycan form and the unusual glycan form of tetraantennary with a limited number of repeating N-acetyllactosamine units. These results further define the covalent structure for the beta-subunit from both lamb and dog kidney (Na,K)-ATPase and suggest that the beta-subunit may be derived from an adhesion molecule.
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PMID:Structures of the complex glycans found on the beta-subunit of (Na,K)-ATPase. 839 Sep 82

Cell adhesion is of utmost importance in normal development and cellular functions. ICAM-5 (intercellular adhesion molecule-5, telencephalin, TLN) is a member of the ICAM family of adhesion proteins. As a novel cell adhesion molecule, ICAM-5 shares many structural similarities with the other members of IgSF, especially the ICAM subgroup; however, ICAM-5 has several unique properties compared to the other ICAMs. With its nine extracellular Ig domains, ICAM-5 is the largest member of ICAM subgroup identified so far. Therefore, it is much more complex than the other ICAMs. The expression of ICAM-5 is confined to the telencephalic neurons of the central nervous system whereas all the other ICAM members are expressed mostly by cells in the immune and blood systems. The developmental appearance of ICAM-5 parallels the time of dendritic elongation and branching, and synapse formation in the telencephalon. As a somatodendrite-specific adhesion molecule, ICAM-5 not only participates in immune-nervous system interactions, it could also participate in neuronal activity, Dendrites' targeting signals, and cognition. It would not be surprising if future investigations reveal more binding partners and other related functions of ICAM-5.
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PMID:Structure, Expression, and Function of ICAM-5. 2231 18

Dendritic filopodia are dynamic structures thought to be the precursors of spines during synapse development. Morphological maturation to spines is associated with the stabilization and strengthening of synapses, and can be altered in various neurological disorders. Telencephalin (TLN/intercellular adhesion molecule-5 (ICAM5)) localizes to dendritic filopodia, where it facilitates their formation/maintenance, thereby slowing spine morphogenesis. As spines are largely devoid of TLN, its exclusion from the filopodia surface appears to be required in this maturation process. Using HeLa cells and primary hippocampal neurons, we demonstrate that surface removal of TLN involves internalization events mediated by the small GTPase ADP-ribosylation factor 6 (ARF6), and its activator EFA6A. This endocytosis of TLN affects filopodia-to-spine transition, and requires Rac1-mediated dephosphorylation/release of actin-binding ERM proteins from TLN. At the somato-dendritic surface, TLN and EFA6A are confined to distinct, flotillin-positive membrane subdomains. The co-distribution of TLN with this lipid raft marker also persists during its endosomal targeting to CD63-positive late endosomes. This suggests a specific microenvironment facilitating ARF6-mediated mobilization of TLN that contributes to promotion of dendritic spine development.
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PMID:ARF6-mediated endosomal transport of Telencephalin affects dendritic filopodia-to-spine maturation. 2278 Nov 29