A domain within the tumor suppressor protein APC shows very similar biochemical properties as the microtubule-associated protein tau.
ABSTRACT The tumor-suppressor protein APC (adenomatous polyposis coli) binds to microtubules and promotes tubulin assembly. In vivo the endogenous APC protein is mainly localized at the end of microtubules that are involved in active cell migration. Since most tumor-specific APC gene mutations lead to the loss of the microtubule binding domain this interaction is assumed to play a crucial role in tumorigenesis. In this study we show that an APC protein fragment (amino acids 2219-2580) within the C-terminal part is enough to bind to non-assembled tubulin with high affinity. The binding of APC to tubulin does not lead to an alteration of the intrinsic GTPase activity of the non-assembled tubulin. The APC protein induces the tubulin assembly in a fast reaction and below the critical assembly concentration of tubulin. The APC protein induces the bundling of the assembled microtubules in a concentration-dependent manner. Regarding its biochemical properties the analysed APC protein fragment strikingly resembles the members of the microtubule-associated protein family tau. This analogy may help to understand the role of the APC protein in the suppression of tumorigenesis.
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ABSTRACT: In the recent years, surface plasmon resonance (SPR) has become one of the major methods for studying and determination of biologically active materials exhibiting affinity interactions. SRP biosensors are increasingly used in biochemistry and bioanalytical chemistry to determine antibody-antigen interactions, to investigate DNA hybridization, to diagnose bacteria- and virus-induced diseases, to identify hormones, steroids, and immunoglobulins, to investigate blood plasma coagulation. Using SPR biosensors, it is possible to analyze the mixtures of substances with a very similar chemical structure because SPR allows identifying only those analytes that specifically interact with biologically active substance immobilized on the surface of SPR biosensor. SPR biosensors are applied to monitor interactions between immobilized biologically active substance and analyte in real-time without labeling. On the other hand, it is possible to investigate not only association of analyte with immobilized material, but also the dissociation of a newly formed complex. SPR biosensors in many cases may be used to perform up to 50 measurements with the same SPR chip with an immobilized biological recognition element. Therefore, at present SPR is one of the most promising methods for determining the interactions between ligand and receptor, antigen and antibody, thus being increasingly used in diagnostics and biomedical research.Medicina (Kaunas, Lithuania) 02/2007; 43(5):355-65. · 0.42 Impact Factor
Article: Programmed ribosomal frameshifting in the expression of the regulator of intestinal stem cell proliferation, adenomatous polyposis coli (APC).[show abstract] [hide abstract]
ABSTRACT: A programmed ribosomal frameshift (PRF) in the decoding of APC (adenomatous polyposis coli) mRNA has been identified and characterized in Caenorhabditis worms, Drosophila and mosquitoes. The frameshift product lacks the C-terminal approximately one-third of the product of standard decoding and instead has a short sequence encoded by the -1 frame which is just 13 residues in C. elegans, but is 125 in D. melanogaster. The frameshift site is A_AA.A_AA.C in Caenorhabditids, fruit flies and the mosquitoes studied while a variant A_AA.A_AA.A is found in some other nematodes. The predicted secondary RNA structure of the downstream stimulators varies considerably in the species studied. In the twelve sequenced Drosophila genomes, it is a long stem with a four-way junction in its loop. In the five sequenced Caenorhabditis species, it is a short RNA pseudoknot with an additional stem in loop 1. The efficiency of frameshifting varies significantly, depending on the particular stimulator within the frameshift cassette, when tested with reporter constructs in rabbit reticulocyte lysates. Phylogenetic analysis of the distribution of APC programmed ribosomal frameshifting cassettes suggests it has an ancient origin and raises questions about a possibility of synthesis of alternative protein products during expression of APC in other organisms such as humans. The origin of APC as a PRF candidate emerged from a prior study of evolutionary signatures derived from comparative analysis of the 12 fly genomes. Three other proposed PRF candidates (Xbp1, CG32736, CG14047) with switches in conservation of reading frames are likely explained by mechanisms other than PRF.RNA biology 07/2011; 8(4):637-47. · 5.56 Impact Factor
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ABSTRACT: We have previously identified in uterine cells a novel estrogen-regulated gene called gec1. GEC1 presents 87% identity with GABARAP which, so far, was the only protein found to associate with tubulin and GABA(A) receptor. We demonstrated then that GEC1 interacts in vitro with tubulin and GABA(A) receptor, and promotes tubulin assembly and microtubule bundling. Since all polyclonal antibodies failed in discrimination of both proteins GEC1 and GABARAP, a GEC1-GFP fusion protein was used to specifically localize GEC1. GEC1-GFP was distributed over the cytoplasm in perinuclear vesicles with a scattered pattern. Overall, our data show that GEC1 could be a new member of the GABARAP family involved in the transport of GABA(A) receptor.Biochemical and Biophysical Research Communications 01/2005; 325(2):639-48. · 2.48 Impact Factor