| IGFBP-6 differs from IGFBP-1 ~ -5 in that it binds IGF-II with marked preferential affinity over IGF-I, and plays the important role in modulation of IGF-II activity. IGFBP-6 is expressed in a range of cells of tumor origin and inhibits IGF-II induced proliferation. Because IGFs play the key role in mammalian growth, fetal differentiation and development, tumor growth and development, the roles of IGFBP family have been the subject of intense study over the past years. During this time, more and more IGF-independent actions of IGFBPs have been described. IGFBP-6 is the latest found member of IGFBP family, and have received relatively little attention. Up to now there are still many questions remain regarding the biological role of IGFBP-6. IGFBP-6 could be important significant since its widely distribution and the special relationship with IGF-II. Our research focus on the follow aspects.Firstly, we expressed and purified the recombinant human IGFBP-6 in Pichia pastoris yeast. Studied the activity of IGFBP-6. Analysed its distribution and location in mammalian cell.1. Constructed the yeast expression vector pAO815-3IGFBP-6 containing 3 copies of IGFBP-6 expression cassette, transformed yeast competent cells, screened the high-level production strain, optimized the expression condition.2. Purified the expression products, and the purity of IGFBP-6 was greater than 90%.3. Tested the action of IGFBP-6 on inhibiting the proliferation activity of IGF-II.4. For the first time, observed that IGFBP-6 could enter the MDA-MB-231 cell and located in nucleus, which would be very helpful for the the study on IGF-independent actions.Secondly, we screened the mouse brain cDNA library using yeast two hybrid system 3. Identified two potential interaction proteins of IGFBP-6. Sequencing and blast analysis showed one is zine finger protein KIAA0530, another is ubiquitin...
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