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Activated Akt acts being a regulating element in inducing SRPK1 autophosphorylation in transducing EGF signaling to manage splicing within the nucleus Getting established an integral function of SRPKs, we next wished to determine how EGF regulates the game of SRPKs. A previous study showed that activated Akt can directly phosphorylate SRPK2, Marimastat ic50 thereby causing huge neuronal death by pushing differentiated neurons to re-enter mitosis. This study mapped the Akt phosphorylation site to Thr491 in the HDRSRT concept positioned in the spacer region of SRPK2, which only loosely matches the Akt opinion RXRXXST. We found no such Akt consensus sequences inside the kinase, raising the question of whether SRPK1 is really a direct substrate for Akt and scanned the amino acid sequence of SRPK1. We therefore took a proteomics way of first decide whether SRPK1 could be phosphorylated in reaction to EGF treatment or overexpression of a constitutively activated Akt. Examination of phosphopeptides by mass spectrometry from immunoprecipitated SRPK1 exposed several phosphorylation sites in SRPK1 that would be induced by Plastid EGF or activated Akt. This statement indicates that SRPK1 may be extensively phosphorylated in vivo, even though that recombinant SRPKs indicated from bacteria are highly active in phosphorylating SR proteins in vitro, implying that several of those phosphorylation events may control other facets of the kinase function in the cell. We used highly purified Akt to phosphorylate bacterially expressed SRPK1, to find out which of the in vivo mapped websites might be direct targets for activated Akt. We found that SRPK1 phosphorylation could be certainly induced by activated Akt in vitro, which could be blocked from the Akt specific inhibitor MK2206. Suddenly, we mentioned that the SRPK1 kinase Apogossypolone dead mutant lost the capability to be phosphorylated by Akt, even though it could compete with WT SRPK1 for binding and phosphorylating an SR protein. Also surprising was the observation that MK2206 alone was able to produce SRPK1 autophosphorylation in the absence of Akt, although it could effectively suppress SRPK1 phosphorylation by Akt. This may be related to the truth that MK2206 is really a non ATP competitive allosteric inhibitor of Akt, which may occupy a regulatory pocket on SRPK1 to stimulate its autophosphorylation. These observations strongly suggest that SRPK1 is licensed by an Akt dependent allosteric mechanism. Akt induces two crucial autophosphorylation activities in SRPK1 The ability of activated Akt to produce SRPK1 autophosphorylation allowed us compare them to people in EGF treated cells and to look for the in-vitro phosphorylation sites by mass spectrometry. This generated the identification of two autophosphorylation sites and two additional sites that have been induced only while in the presence of active Akt, one situated in the spacer domain and another in the C terminal region of SRPK1. More consistent with the possibility that these phosphorylation events result from autophosphorylation may be the observation that a fragment of SRPK1 containing T326 couldn't be phosphorylated with pure Akt.