A-kinase anchor proteins in endocrine systems and reproduction.
ABSTRACT Over the past few years, significant progress has been made in characterizing the expression and localization of proteins that act as scaffolds for cAMP-dependent protein kinase (PK-A). These A-kinase anchor proteins (AKAPs) tether PK-A to intracellular organelles and structures, sequestering the kinase near its physiological substrates. The compartmentalization of distinct pockets of PK-A activity serves to provide spatial regulation of this signaling pathway. In addition, other signaling proteins bind to AKAPs, as do some newly described proteins of unknown function, suggesting that proteins of various pathways are anchored through AKAPs.
Article: AKAP7γ is a nuclear RI-binding AKAP[Show abstract] [Hide abstract]
ABSTRACT: Spatial regulation of protein kinase A (PKA) is accomplished by its sequestration via A-kinase anchor proteins (AKAPs). PKA activity is critical for mammalian oocyte development, suggesting that PKA must be appropriately positioned in these large cells. A screen for AKAPs in oocytes identified AKAP7γ, an AKAP originally found in pancreas. Yeast two-hybrid analysis and co-immunoprecipitation studies showed that AKAP7γ bound the type I PKA regulatory subunit (RI) and that the RI-binding domain overlapped the previously identified type II PKA regulatory subunit (RII) binding domain. Overexpressed AKAP7γ localized to the nuclei of HEK 293 cells via a nuclear localization signal. In addition, endogenous AKAP7γ protein was found in both the nucleus and cytoplasm of oocytes. This work identifies AKAP7γ as the first nuclear AKAP to bind RI and suggests that AKAP7γ may be responsible for positioning PKA via RI and/or RII to regulate PKA-mediated gene transcription in both somatic cells and oocytes.Biochemical and Biophysical Research Communications 06/2003; DOI:10.1016/S0006-291X(03)00982-3 · 2.28 Impact Factor
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ABSTRACT: A 3-dimensional baroclinic model of the North Sea and the Baltic Sea has delivered operational forecasts since 1995. The model is mainly forced by the operational atmospheric model (HIRLAM) at the Swedish Meteorological and Hydrological Institute (SMHI), but also by monthly means of river runoff and wave radiation stress from a wind wave model. The model is running with a nested grid, where a 12 nautical mile grid covers the whole area while Skagerrak, Kattegat, the Belt Sea and the Baltic Sea is covered with a 3 nautical mile grid.A crucial parameter in ocean modelling is how well the model resolves the meso-scale dynamics with a scale of the same order as the internal Rossby radius. For the Baltic Sea, this scale is roughly from 3 to 6 km, i.e. of the same size as the present resolution of 3 nautical miles. When moving to a massive parallel computer with distributed memory, it is now possible to increase the resolution to 1 nautical mile and still run a 48-hours forecast within 1 hour CPU-time.The parallelisation has been performed in two steps. At first the whole computational domain has been partitioned into a large number of rectangular blocks to avoid inactive land-points. The blocks have then been projected into the number of available parallel processors. Secondly, a set of F90 modules have been developed to manage the different grids and blocks while hiding parallelisation details. Only one grid block at a time is presented to the original F77 code. Finally, a new solver has been introduced for the linear equation systems for water level and sea ice dynamics, which now are solved with a distributed multi-frontal solver.We have found that the production of HIROMB, forecasts can successfully be moved from the present vector computer C90 to the massive parallel computer T3E while increasing the resolution from 3 to 1 nautical mile. However, speedup and load balance could still be further improved.
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ABSTRACT: In many marine fish species, the spermatozoa are immotile in the testis and seminal plasma, and motility is induced when they are released in the aqueous environment. It is well known that the extracellular factors (hyperosmolality or sperm-activating peptides), controlling sperm motility in marine fish, act on the axonemal apparatus through signal transduction across the plasma membrane. To better understand the molecular mechanism regulating axoneme activation in marine fish, the present review examines the existing literature, with particular emphasis on protein phosphorylation/dephosphorylation process. The present review suggests that: (1) there is no single model that can explain the molecular activation and regulation of sperm motility of the marine fish; (2) only in some species (puffer fish, tilapia, gilthead sea bream, and striped sea bream) protein phosphorylation/dephosphorylation has been shown to be involved in flagellar motility regulation; (3) only a few proteins were identified, which show a change in their state of phosphorylation following sperm activation. A model of molecular mechanism controlling the activation of sperm motility in gilthead sea bream is being proposed here, which could be a useful model to clarify the sperm motility activation process in other species.01/2012; 4(1). DOI:10.1186/2008-6970-4-2