Why is the actual band size on a western blot different from the predicted size of the protein?
Western blotting is based on the separation of proteins by their size on a gel. However, migration of proteins through the gel matrix is also affected by other factors, which may cause the observed band size to be different from the predicted size.
Common causes are:
-Post-translational modification; for example phosphorylation and glycosylation increase the size of the protein
-Post-translation cleavage; many proteins are synthesized as precursor proteins, and then cleaved to give the active form
-Multimers, for example dimerization of a protein. This is usually prevented under reducing conditions, although strong interactions can result in the appearance of higher bands
-Splice variants; alternative splicing may result in different sized proteins being produced from the same gene
-Relative charge; the composition of amino acids (charged vs. non-charged)
Dexras1/AGS-1 inhibits signal transduction from the Gi-coupled formyl peptide receptor to Erk-1/2 MAP kinases.
Authors: Graham Timothy E; Prossnitz Eric R; Dorin Richard I;
Journal:J Biol Chem
PubMed ID:11751935
'Dexras1 is a novel GTP-binding protein (G protein) that was recently discovered on the basis of rapid mRNA up-regulation by glucocorticoids in murine AtT-20 corticotroph cells and in several primary tissues. The human homologue of Dexras1, termed activator of G protein signaling-1 (AGS-1), has been reported to stimulate signaling by ... More
In Saccharomyces cerevisiae, the inositol polyphosphate kinase activity of Kcs1p is required for resistance to salt stress, cell wall integrity, and vacuolar morphogenesis.
Authors: Dubois Evelyne; Scherens Bart; Vierendeels Fabienne; Ho Melisa M W; Messenguy Francine; Shears Stephen B;
Journal:J Biol Chem
PubMed ID:11956213
A problem for inositol signaling is to understand the significance of the kinases that convert inositol hexakisphosphate to diphosphoinositol polyphosphates. This kinase activity is catalyzed by Kcs1p in the yeast Saccharomyces cerevisiae. A kcs1Delta yeast strain that was transformed with a specifically ... More
Angiogenic bFGF expression from gas-plasma treated scaffolds.
Authors:Bailey SR, Polan JL, Morse B, Wetherold S, Villanueva-Vedia RE, Waggoner D, Phelix C, Barera-Roderiquiz E, Goswami N, Munoz O, Agrawal CM,
Journal:Cardiovasc Radiat Med
PubMed ID:12974371
PURPOSE: In vivo experiments indicate that gas-plasma-treated D,L-polylactide polymers expressing basic fibroblast growth factor (bFGF) exhibit enhanced angiogenesis. bFGF is not a single entity, but it is instead a family of isoforms. Consequently, we sought to determine which bFGF isoforms and levels initiate angiogenesis in nude mice peritoneums. METHODS: Cytoplasmic ... More
Mutations of the gene encoding the protein kinase A type I-alpha regulatory subunit in patients with the Carney complex.
Authors: Kirschner L S; Carney J A; Pack S D; Taymans S E; Giatzakis C; Cho Y S; Cho-Chung Y S; Stratakis C A;
Journal:Nat Genet
PubMed ID:10973256
Carney complex (CNC) is a multiple neoplasia syndrome characterized by spotty skin pigmentation, cardiac and other myxomas, endocrine tumours and psammomatous melanotic schwannomas. CNC is inherited as an autosomal dominant trait and the genes responsible have been mapped to 2p16 and 17q22-24 (refs 6, 7). Because of its similarities to ... More
Opposing action of estrogen receptors alpha and beta on cyclin D1 gene expression.
Authors: Liu Meng-Min; Albanese Chris; Anderson Carol M; Hilty Kristin; Webb Paul; Uht Rosalie M; Price Richard H Jr; Pestell Richard G; Kushner Peter J;
Journal:J Biol Chem
PubMed ID:11986316
Induction of cyclin D1 gene transcription by estrogen receptor alpha (ERalpha) plays an important role in estrogen-mediated proliferation. There is no classical estrogen response element in the cyclin D1 promoter, and induction by ERalpha has been mapped to an alternative response element, a cyclic AMP-response element at -57, with possible ... More