Conserved pathways

Biogenic amines are decarboxylated derivatives of tyrosine and tryptophan that are found in animals from simple invertebrates to mammals. These compounds are found in neural tissue, where they function as neurotransmitters, and in non-neural tissues, where they have a variety of functions. The enzymes involved in biogenic amine synthesis and many receptors for these compounds have been isolated from both invertebrate and vertebrate sources. In all cases, the individual proteins that effect biogenic amine metabolism and function show striking similarity between species, indicating that these are ancient and well-conserved pathways. 

Holtum Winter, 1982) and during C4 development (e.g. Nelson Langdale, 1989). It is to be hoped that in addition to more work on gene structure and expression, additional work will be focused on the biochemistry and structure of the enzymes. Interest in the developmental aspects of the establishment of the C4 pathway, in plants such as Flaveria (Adams et al., 1986) that contain interfertile C3, C3/C4 intermediate, and C4 species, and in CAM as a water-conserving pathway, should be sufficient reason to do this. 

Pawson, T. (1993) Signal transduction—a conserved pathway from the membrane to the nucleus. Dev. Genet. 14, 333-338. 

Kelley, B.P., Sharan, R., Karp, R.M., Sittler, T., Root, D.E., Stockwell, B.R. and Ideker, T. (2003) Conserved pathways within bacteria and yeast as revealed by global protein network alignment. Proc. Natl Acad. Sci. U.S.A. 100, 11394-11399. 

Besharse, J.C., Baker, S.A., Luby-Phelps, K. and Pazour, G.J. (2003a) Photoreceptor intersegmental transport and retinal degeneration a conserved pathway common to motile and sensory cilia. Adv. Exp. Med. Biol. 533,157-164. 

Oxygen. The deactivation of O ( D2) by O2 is interesting for it offers several exoergic spin-conserving pathways leading to electronic excitation of the collision partner,... 

Another approach used to infer human functional significance from animal data is to focus on conserved pathways between species. There is experimental evidence to show that innate immunity is conserved across nematodes,... 

In contrast, methylation at K4 of H3 is correlated with transcriptionally active states of chromatin. The K4 methylation appears to be absent from histones with methylation at K9, but colocalizes with acetylation at K9, indicating a positive cooperation of acetylation and methylation of distinct Lys residues during the establishment of a transcriptionally active state. For yeast histones, a link between methylation and acetylation at Lys residues and phosphorylation at Ser residues of histone H3 has been discovered (Nakayamaet al.,., 2001), defining a conserved pathway of sequential histone modifications during heterochromatin assembly. These modifications are recognized by specific proteins that are part of multiprotein assemblies in heterochromatin. 

NOTCH proteins participate in conserved pathways that regulate cellular differentiation, proliferation, and cell death. Mammalian NOTCH receptors are single-pass transmembrane proteins that transmit juxtacrine signals initiated by ligands of the Delta, Serrate, or Lag-2 family [122, 123], When ligands bind to the extracellular domain of NOTCH1, sequential proteolytic processing events lead to the... 

Moco biosynthesis is an ancient, ubiquitous, and highly conserved pathway leading to the biochemical activation of molybdenum. Mutations in the human Moco biosynthetic genes lead to death in early childhood. The affected patients show severe neurological abnormalities such as attenuated growth of the brain, seizures, and dislocated ocular lenses. So far, no effective therapy is available to cure the disease. 

Lockless SW, Ranganathan R. 1999. Evolutionaiily conserved pathways of energetic connectivity in protein famihes. Science 286 295-299. 

Zhang, X. et al (2009) Metabolic evolution of energy-conserving pathways for succinate production in Escherichia coli. Proc. Natl. Acad. Scl U.S.A., 106, 20180-20185. 

One other DNA repair system of particular relevance for maintaining genomic stability is MMR. This evolutionary conserved pathway is responsible for the repair of mismatched normal bases after DNA replication, contributing significantly to the extraordinary fidelity of DNA replication. Cells deficient in MMR exert a mutator phenotype , in which the rate of spontaneous mutations is greatly elevated, and defects in MMR are associated with an increased risk of different types of cancer. 

Cyclic electron transfer around photosystem I (PSI) can be considered as an important energy-conserving pathway in plant photosynthesis. Its operation requires ferredoxin as a cofactor while its activity is strongly dependent on a proper redox balance of the electron carriers. 

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