Phosphatase isoform

Brun-Heath I, Ermonval M, Chabrol E et al (2011) Differential expression of the bone and the liver tissue non-specific alkaline phosphatase isoforms in brain tissues. CeU Tissue Res 343 521-536... 

Hailing LC, Narisawa S, MiUan JL et al (2009) Glycosylation differences contribute to distinct catalytic properties among bone aUcaline phosphatase isoforms. Bone 45 987-993... 

Janckila AJ, Nakasato YR, Neustadt DH et al (2003) Disease-specific expression of tartrate-resistant acid phosphatase isoforms. J Bone Miner Res 18 1916-1919... 

Gibbons JA, Kozubowski L, Tatchell K et al (2007) Expression of human protein phosphatase-1 in Saccharomyces cerevisiae highlights the role of phosphatase isoforms in regulating eukaryotic functions. J Biol Chem 282 21838-21847... 

Roche, T.E. Baker, J.C. Yan, X. Hiromasa, Y Gong, X. Peng, T. Dong, J. Turkan, A. Kasten, S.A. Distinct regulatory properties of pyruvate dehydrogenase kinase and phosphatase isoforms. Prog. Nucleic Acid Res. Mol. Biol., 70, 33-75 (2001)... 

Ouimet, C.C., daCruz, E., Silva, E.F., Greengard, P. The alpha and gamma 1 isoforms of protein phosphatase 1 are highly and specifically concentrated in dendritic spines. Proc. Natl. Acad. Sci. U.S.A. 92 3396, 1995. 

In general, the 10 different forms of adenylyl cyclase can be divided into three major and two minor groups based on their functional attributes as well as on their sequence homology. The three major families are (1) the Ca2+/calmodulin-stimulated isoforms, which include AC1, AC3, and AC8 certain of these enzymes are inhibited by GPt (2) the G[ -stimulated isoforms, which include AC2, AC4, and AC7 and (3) the Ca2+ and Gai inhibited isoforms, which are AC5 and AC6. The other two categories each have a single member (4) AC9, which is the most divergent of the membrane-bound isoforms, is stimulated by G(IS, inhibited by calcineurin (a protein phosphatase), and is insensitive to forskolin (5) sAC, the only soluble isoform, is the most divergent and is most similar to the adenylyl cyclase found in Cyanobacteria. 

Protein phosphatase 1. Four subtypes of PP1, derived from three genes, are known. These enzymes, listed in Table 23-2, are highly homologous and exhibit similar substrate specificities therefore, they can be considered isoforms. However, the proteins exhibit very distinct patterns of distribution in the brain. PP1 dephosphorylates a wide array of substrate proteins. Its catalytic subunit can form complexes with over 50 regulatory subunits in a... 

Alkaline phosphatase is an enzyme represented by various isoforms in many tissues such as liver, bone, intestine, placenta, some tumors and in leukocytes. Addition of 1 mM levamisole to the chromogen/substrate will inhibit endogenous alkaline phosphatase activity, with the exception of the intestinal isoform. If necessary, this can be blocked with a weak acid wash, such as 0.03 0.5 N HC1 or 1 M citric acid. 

Ceramide-activated protein phosphatase Protein kinase C isoforms alpha, delta and zeta c-Raf-1 ... 

Cycling protein phosphorylation plays a role in the mammalian circadian clock as well. PERI, PER2 and BMAL all show temporal changes in electrophoretic mobility that are eliminated by phosphatase treatment (Lee et al 2001). Although these PER phosphorylations are likely to reflect CKl activity they may not be the only clock-related substrates of this enzyme family. CRYl and CRY2, for instance, can be phosphorylated by CKls in vitro when present in a CRY/PER/CKle complex (Eide et al 2002). Two isoforms of mammalian CLOCK (orthologue of Drosophila CLK) also appear to be phosphorylated, resulting in mobility shifts by Western analysis (Lee et al 2001). The kinase(s) responsible for CLOCK phosphorylation is (are) unknown. 

Usuda, N., Arai, H., Sasaki, H., Hanai, T., Nagat, T., Muramatsu, T., Kincaid, R. L., and Higuchi, S. 1996. Differential subcellular localization of neural isoforms of the catalytic subunit of calmodulin dependent protein phosphatase (calcineurin) in central nervous system neurons Immunohistochemistry on formalin-fixed paraffin sections employing antigen retrieval by microwave irradiation. J. Histochem. Cytochem. 44 13-18. 

Although CsA and FK506 are extremely selective inhibitors of calcineurin, some of the studies above indicate that these drugs could possibly have calcineurin-independent elfects. Moreover, calcineurin shows phosphatase activity towards a wide variety of phosphoprotein substrates, and inhibition of calcineurin by immunosuppressant-immunophilin complexes blocks phosphatase activity toward a broad spectrum of phos-phoproteins. Inhibitors that blocked calcineurin mediated dephosphorylation of a specific substrate (such as NF-AT, or specific isoforms of NF-AT) without affecting the dephosphorylation of other substrates would be of great therapeutic as well as academic interest. The search for... 

Kambayashi, Y., Bardhan, S., Takahashi, K., et al. 1993. Molecular cloning of a novel angiotensin II receptor isoform involved in phosphotyrosine phosphatase inhibition. J Biol Chem 268 24543-24546. 

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