title: Interaction of proteins identified in human thyroid cells.
abstract: Influence of gravity forces on the regulation of protein expression by healthy and malignant thyroid cells was studied with the aim to identify protein interactions. Western blot analyses of a limited number of proteins suggested a time-dependent regulation of protein expression by simulated microgravity. After applying free flow isoelectric focusing and mass spectrometry to search for differently expressed proteins by thyroid cells exposed to simulated microgravity for three days, a considerable number of candidates for gravi-sensitive proteins were detected. In order to show how proteins sensitive to microgravity could directly influence other proteins, we investigated all polypeptide chains identified with Mascot scores above 100, looking for groups of interacting proteins. Hence, UniProtKB entry numbers of all detected proteins were entered into the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and processed. The program indicated that we had detected various groups of interacting proteins in each of the three cell lines studied. The major groups of interacting proteins play a role in pathways of carbohydrate and protein metabolism, regulation of cell growth and cell membrane structuring. Analyzing these groups, networks of interaction could be established which show how a punctual influence of simulated microgravity may propagate via various members of interaction chains.
authors.affiliation: Plastic, Aesthetic and Hand Surgery, Otto-von-Guericke University Clinic, Leipziger Str. 44, 39120 Magdeburg, Germany. daniela.grimm@farm.au.dk.
authors.forename: Jessica
authors.initials: J
authors.lastname: Pietsch
authors.forename: Stefan
authors.initials: S
authors.lastname: Riwaldt
authors.forename: Johann
authors.initials: J
authors.lastname: Bauer
authors.forename: Albert
authors.initials: A
authors.lastname: Sickmann
authors.forename: Gerhard
authors.initials: G
authors.lastname: Weber
authors.forename: Jirka
authors.initials: J
authors.lastname: Grosse
authors.forename: Manfred
authors.initials: M
authors.lastname: Infanger
authors.forename: Christoph
authors.initials: C
authors.lastname: Eilles
authors.forename: Daniela
authors.initials: D
authors.lastname: Grimm
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D019295:Computational Biology / Q000379:methods*; D006801:Humans; D007525:Isoelectric Focusing / Q000379:methods; D013058:Mass Spectrometry; D008954:Models, Biological; D011485:Protein Binding; D025941:Protein Interaction Mapping / Q000379:methods; D060066:Protein Interaction Maps; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D015398:Signal Transduction; D013961:Thyroid Gland / Q000378:metabolism*; D018474:Weightlessness Simulation
chemical_list: D020543:Proteome