Activity map

The output-activity map. A trained Kohonen network yields for a given input object, X, one winning unit, whose weight vector, is closest (as defined by the criterion used in the learning procedure) to x,. However, X may be close to the weight vectors, w, of other units as well. The output yj of the units of the map can also be defined as ... 

D is the similarity measure as used in the training procedure. This results in a map as in Fig.44.26a. This map allows the inspection of regions (neighbouring neurons) that have a similar weight vector as a given input x,. Note that each input x, yields a different output activity map. 

Gomez, N., and Cohen, P. (1991). Dissection of the protein kinase cascade by which nerve growth factor activates MAP kinases. Nature 353 170-173. 

Gotoh, Y., Nishida, E Matsuda, S., Shiina, N., Kosako, H Shiokawa, K., Akiyama, T., Ohta, K., and Sakai, H. (1991 a). In vitro effects on microtubule dynamics of purified Xenopus M phase-activated MAP kinase. Nature 349 251-254. 

The activated MAP kinase exposes a signal peptide that enables it to interact with proteins that promote its translocation into the nucleus. Inside, it catalyzes the phosphorylation of its substrates on Ser-Pro and Thr-Pro motifs. In the case of stimulation by EGF and PDGF, the activation of... 

Zecevic M, Catling AD, Eblen ST et al 1998 Active MAP kinase in mitosis localization at kinetochores and association with the motor protein CENP-E. J Cell Biol 142 1547—1558... 

The very beginning of the first mitotic cell cycle of the mouse embryo seems to be controlled by the mechanisms characteristic for both meiotic and mitotic cell cycles. Active MAP kinase, its substrate p90rsk and the CSF activity itself could influence the cellular processes within the one-cell embryo. Indeed, we have observed that despite the entry into the interphase (as judged by the low activity of MPF) some proteins are actively phosphorylated as during the meiotic M phase (e.g. 35 kDa complex Howlett et al 1986, Szollosi et al 1993), the nuclei and the microtubule interphase network start to form only 1.5 hours after activation (Szollosi et al 1993). This delay in the phenomena characteristic for the interphase could be linked to the mixed meiotic/mitotic character of this early period. This delay probably allows the correct transformation of the sperm nucleus into the male pronucleus. In species like Xenopus or Drosophila the transitional period between the meiotic and the mitotic cell cycle control is probably much shorter since it is proportional to duration of the short first cell cycle of these rapidly cleaving embryos. Mammalian embryos are perhaps the most suitable to study this transition because of the exceptionally long first embryonic cell cycle. 

Knowles, R. B., Chin, J., Ruff, C. T. and Hyman, B. T. (1999). Demonstration by fluorescence resonance energy transfer of a close association between activated MAP kinase and neurofibrillary tangles Implications for MAP kinase activation in Alzheimer disease. J. Neuropathol. Exp. Neurol. 58, 1090-8. 

The kinases themselves can be arranged into phosphorylation cascades so that one kinase phosphorylates another, which, in turn, phos-phorylates another. This often leads to some funny names, such as MAP kinase kinase kinase. This means a mitogen-activated protein kinase that phosphorylates MAP kinase kinase. The activated MAP kinase kinase then phosphorylates and activates MAP kinase. 

MAP kinase Mitogen-activated MAP kinase Cell growth... 

Improta G, Zupa A, Fillmore H et al (2001) Protein pathway activation mapping of brain metastasis from lung and breast cancers reveals organ type specific drug target activation. J Proteome Res 10 3089-3097... 

Accord B, Espina V, Giordan M et al (2010) Functional protein network activation mapping reveals new potential molecular drug targets for poor prognosis pediatric BCP-ALL. PLoS One (Electronic Resource) 5 el3552... 

Topographic mapping of the EEG, also referred to as brain electrical activity mapping, involves the recording of cortical electrical activity in certain specified frequencies, which a computer then graphically visualizes in two-dimensional, color-coded maps. This procedure is chiefly used in psychopharmacological and neuropsychological research. 

Burden, F.R. and Winkler, D.A. 1999. New QSAR methods applied to structure-activity mapping and combinatorial chemistry. J. Chem. Inf. Corn-put. Sci. 39 236-242. 

Hermani A, De Servi B, Medunjanin S, Tessier PA, Mayer D. 2006. S100A8 and S100A9 activate MAP kinase and NF-kappaB signaling pathways and trigger translocation of RAGE in human prostate cancer cells. Exp Cell Res 312(2) 184—197. 

Figure 17 shows the measured spatially resolved mass activity map for the aged MEA from the controlled start-stop test in comparison with a new one.55 It also indicates more carbon loss near the anode inlet, because one can easily imagine that when carbon support particles collapse, the platinum particles can come in contact with one another, which leads to coalescence of the platinum... 

A third screening method for arrays of electrocatalysts was recently introduced by Hillier and coworkers [15, 29, 30]. Using a scanning electrochemical microscope (SECM), a microelectrode tip is moved over an electrocatalyst array. The resulting electrochemical feedback currents are measured and used to generate an activity map of the electrocatalyst library. This method does not require individual electronic addressability for each electrocatalyst... 

Lenormand P, Sardet C, Pages G, L Allemain G, Brunet A, Pouyssegur J. 1993. Growth factors induce nuclear translocation of MAP kinases (p42mapk and p44mapk) but not of their activator MAP kinase kinase (p45mapkk) in fibroblasts. J Cell Biol 122 1079-1088. 

FIGURE 33.5 Activation map superimposed on coronal anatomical MR images in a right-handed subject, in response to passive stimulation, (a) Skin to skin, (b) Perception of a tactile stimulation, (c) Skin to skin with a skin-care product. I Ipsilateral, C Contralateral.13... 

Figure 6. Scheme to represent known aspects of the plasma membrane NADH oxidase and its association with proton release. The oxidase is activated when hormones or ferric transferrin bind receptors. Oxidase may activate tyrosine kinase which can activate MAP kinases to result in phosphorylation of the exchanger leading to Na+/H+ exchange. Oxidation of quinol in the membrane can also release protons to the outside equal to the number of electrons transferred. External ferricyanide can activate electron flow by accepting electrons at the quinone. G proteins (GTP binding proteins) such as ras-activate electron transport and proton release in some way and may be a link to kinase activation (McCormick, 1993). Semiquinone formation in the membrane could lead to superoxide and peroxide formation by one electron reduction of oxygen. 

S. J. Mansour, et al. Transformation of mammalian cells by constimtively active MAP kinase kinase. Science, 265, 966-970, 1994. 

As shown in the laboratory of R. J. Lefkowitz by Luttrell et al. and Lin et activation of c-Src and the MAP kinase by arrestin is coupled to P2"AR and its removal from the membrane via clathrin-coated pits. Arrestin mutants that can not interact with clathrin are unable to internalize the receptor and to activate c-Src and MAP kinases. On the other hand, arrestin mutants that interact poorly with c-Src kinase, but interact with clathrin, are still functional in receptor sequestration, but can no longer activate MAP kinases in a P2-AR-dependent manner. 

This raises the question of how the linker function of arrestin is regulated. A likely possibility is phosphorylation dephosphorylation, because the free, unbound cytosolic form of arrestin is phosphorylated and is dephosphorylat-ed on binding to the receptor. Moreover, only dephospho-rylated arrestin can interact with c-Src kinase and activate MAP kinase. Luttrell ec al. showed that arrestin interacts... 

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