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Mi-2β is the main component of the nucleosome remodeling and deacetylase complex and plays an important role in epigenetic transcriptional repression. Here we show that the amino-terminal and carboxyl-terminal regions of Mi-2β have distinct transcriptional activities and bind to BRG1, a component of the SWI/SNF complex, and the RET finger protein (RFP), respectively. Analysis by luciferase reporter assay revealed that the amino-terminal region of Mi-2β has a strong transactivating ability, whereas its carboxyl-terminal region has transcriptional repressive activity. Co-localization and association of Mi-2, RFP, and histone deacetylase 1 suggested that these proteins cooperate in transcriptional repression. Furthermore, the functional importance of the association of Mi-2β and RFP was confirmed by using Rfp[sup -/-] fibroblasts. On the other hand, we demonstrated that Mi-2 and BRG1 were associated with each other and that the bromodomain region of BRG1 strongly suppressed transactivation by the amino-terminal region of Mi-2β. The findings that Mi-2β interacts with both transactivating and repressing proteins and directly associates with another chromatin remodeling protein, BRG1, provide new insight into the formation of multiprotein supercomplex involved in transcriptional regulation. [ABSTRACT FROM AUTHOR]

Summary: The serine/threonine kinase Akt (also called protein kinase B) is well known as an important regulator of cell survival and growth and has also been shown to be required for cell migration in different organisms. However, the mechanism by which Akt functions to promote cell migration is not understood. Here, we identify an Akt substrate, designated Girdin/APE (Akt-phosphorylation enhancer), which is an actin binding protein. Girdin expresses ubiquitously and plays a crucial role in the formation of stress fibers and lamellipodia. Akt phosphorylates serine at position 1416 in Girdin, and phosphorylated Girdin accumulates at the leading edge of migrating cells. Cells expressing mutant Girdin, in which serine 1416 was replaced with alanine, formed abnormal elongated shapes and exhibited limited migration and lamellipodia formation. These findings suggest that Girdin is essential for the integrity of the actin cytoskeleton and cell migration and provide a direct link between Akt and cell motility. [Copyright &y& Elsevier]

In the developing kidney, activation of the rearrangement during transfection by glial cell line-derived neurotrophic factor (GDNF) is required for normal branching of the ureteric bud epithelium. By differential display analysis we identified a novel GI)NF-inducible gene (named GZF1) with a BTB/POZ (broad complex, tramtrack, and bric-a-brac)/(poxvirus and zinc finger) domain and 10 tandemly repeated zinc finger motifs. The up-regulation of the GZF1 gene showed two peaks at 1 h and 24-48 h after GDNF stimulation by Northern blotting. The late induction was also found at protein levels by Western blotting with anti-GZF1 antibody. As observed for other proteins with the BTB/POZ domain, the GZF1 protein had strong transcriptional repressive activity. Intriguingly, its expression was detected at high levels in branching ureteric buds and collecting ducts of mouse metanephric kidney in which RET was also expressed. Antisense phosphorothioated oligodeoxynucleotides of the GZF1 gene markedly impaired the ureteric bud branching in the metanephric organ culture, suggesting that the induction of GZF1 expression via the GDNF/RET signaling system is required for renal branching morphogenesis. [ABSTRACT FROM AUTHOR]

Presents a correction to the article "Identification of a Novel Glial Cell Line-Derived Neurotrophic Factor-Inducible Gene Required for Renal Branching Morphogenesis," that was previously published in the periodical "Journal of Biological Chemistry".