Signaling pathway convergent

SIGNAL INTEGRATION by phosphorylase kinase. Phosphorylase kinase eventually phosphorylates and activates glycogen phosphorylase. Either (or both) phosphorylation and calcium signaling pathways converge at phosphorylase kinase. 

Ma, Y., Brewer, J.W., Diehl, J.A. and Hendershot, L.M. (2002) Two distinct stress signaling pathways converge upon the CHOP promoter during the mammalian unfolded protein response. J. Mol. Biol. 318, 1351-1365. 

The Jak/STAT pathway is not the only pathway by which STAT proteins transmit signals to the level of transcription. Over 40 different proteins have been identified that induce phosphorylation and activation of STAT proteins, and several signaling pathways converge at the level of the STAT proteins. Stat proteins can be activated via... 

Ahlers A, Belka C, Gaestel M, et al. Interleukin-1-induced intracellular signaling pathways converge in the activation of mitogen-activated protein kinase and mitogen-activated protein kinase-activated protein kinase 2 and the subsequent phosphorylation of the 27-kilodalton heat shock protein in monocytic cells. Mol Pharmacol 1994 46 1077-1083. 

Figure 43-13. Several signal transduction pathways converge on CBP/p300. Ligands that associate with membrane or nuclear receptors eventually converge on CBP/p300. Several different signal transduction pathways are employed. EGF, epidermal growth factor GH, growth hormone PrI, prolactin TNF, tumor necrosis factor other abbreviations are expanded in the text.

The transcription factors AP-1 and NFkB are at the end of a signal cascade activated by growth factors (see chapters 9,10,11), The ability of steroid hormone receptors in certain situations to nullify the effect other transcription factors demonstrates that two different signaling pathways can converge at the level of transcription. 

Phosphorylated IRS-1 activates a second signaling pathway by interacting with an 85-kDa SH2-containing protein that is a subunit of phophatidylinositol 3-kinase.384 386 This activates the 110-kDa catalytic subunit of the 3-kinase, which catalyzes formation of phosphatidylinositol 3-phosphate as well as Ptdlns (3,4)P2 and Ptdlns (3,4,5)P3.387/387a These compounds, which remain within membranes, activate other branches of the signaling cascade, some of which may converge with those of the MAP kinase cascade. However, there appears to be specific activation of a ribosomal Ser/Thr kinase that, among other activities, phosphorylates ribosomal protein S6, a component of the small ribosomal subunit.388 It also phosphorylates some isoforms of protein kinase C and other enzymes. Ptdlns 3-kinase may also activate 6-phosphofructo-2-kinase (Fig. 11-2, step ti).384/388... 

Vandenbussche F, Habricot Y, Condiff AS, Maldiney R, Van Der Straeten D, Ahmad M. 2007. HY5 is a point of convergence between crytochrome and cytokinin signaling pathways in Arabidopsis thaliana. Plant J 49 428-441. 

In primary cultures of neonatal cerebellar granule neurons, all Ca2+ sensors, calmodulin, protein kinases C (PKC), and the p21(ras)/phosphatidylinositol 3 -kinase (Ptdlns-3K)/Akt pathway, converge towards NF-kB at the levels of nuclear translocation as well as transcription. The duration of NF-kB activation is a critical determinant for sensitivity toward excitotoxic stress and is dependent on the different upstream and downstream signaling associated with various kinases. This is in contrast to studies in non-neuronal cells, which either do not respond to Ca2+ or do not simultaneously activate all three cascades (Lilienbaum and Israel, 2003). Collective evidence suggests that brain inflammatory processes differ from systemic inflammation not only in the involvement of various types of neural cells but also in differences in response to second messengers. 

Chao, M. V. (2003). Neurotrophins and their receptors A convergence point for many signalling pathways. Nature Rev. Neurosci. 4, 299-309. 

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