Scaffold proteins regulate intracellular MAP kinase signaling by providing critical spatial and temporal specificity. We have shown previously that the scaffold protein MEK1 partner (MP1) is localized to late endosomes by the adaptor protein p14. Using conditional gene disruption of p14 in livers of mice we analysed protein and transcript signatures in tissue samples. Further biological network analysis predicted that the differentially expressed transcripts and proteins are involved in cell cycle progression and regulation of cellular proliferation. Although some of the here identified signatures were previously linked to phospho-ERK activity, most of them were novel targets of late endosomal p14/MP1/MEK/ERK signaling module. Finally, the proliferation defect was confirmed in a chemically induced liver regeneration model in p14 liver knock-out mice.
Comprehensive proteomic and transcriptomic characterization of hepatic expression signatures affected in p14 liver conditional knockout mice.
Specimen part
View SamplesThe subunits of voltage-gated calcium channels regulate surface expression and gating of CaV1 and CaV2 1 subunits, and thus contribute to neuronal excitability, neurotransmitter release and calcium-induced gene regulation. In addition certain subunits are targeted into the nucleus, where they directly interact with the epigenetic machinery. Whereas their involvement in this multitude of functions is reflected by a great molecular heterogeneity of isoforms derived from four genes and abundant alternative splicing, little is known about the roles of individual variants in specific neuronal functions. In the present study, an alternatively spliced 4 subunit lacking the variable N-terminus (4e) is identified. It is highly expressed in mouse cerebellum and cultured cerebellar granule cells (CGC) and modulates P/Q-type calcium currents in tsA cells and CaV2.1 surface expression in neurons. Compared to the other two known full-length 4 variants (4a, 4b) 4e is most abundantly expressed in the distal axon, but lacks nuclear targeting properties. To examine the importance of nuclear targeting of 4 subunits for transcriptional regulation, we performed whole genome expression profiling of CGCs from lethargic mice individually reconstituted with 4a, 4b, and 4e. Notably, the number of genes regulated by each 4 splice variant correlated with the rank order of their nuclear targeting properties (4b> 4a> 4e). Together these findings support isoform-specific functions of 4 splice variant in neurons, with 4b playing a dual role in channel modulation and gene regulation, while the newly detected 4e variant serves exclusively in calcium channel-dependent functions.
Differential neuronal targeting of a new and two known calcium channel β4 subunit splice variants correlates with their regulation of gene expression.
Specimen part
View SamplesGlucocorticoids (GC) are in most chemotherapy protocols for lymphoid malignancies, particularly childhood acute lymphoblastic leukaemia (ALL) for their ability to induce apoptosis in malignant blast. The underlying mechanism, however, has so far only been investigated in model systems. This study comprises Affymetrix hgu133 plus 2.0 analyses of
Identification of glucocorticoid-response genes in children with acute lymphoblastic leukemia.
No sample metadata fields
View Samples