Molecular cloning of a novel isotype of Mg2+-dependent protein phosphatase β (type-2Cβ) enriched in brain and heart

Takayuki Terasawa, Takayasu Kobayashi, Takashi Murakami, Motoko Ohnishi, Shunsuke Kato, Osamu Tanaka, Hisatake Kondo, Hiroaki Yamamoto, Takuji Takeuchi, Shinri Tamura

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    41 Citations (Scopus)


    Two complementary DNA (cDNA) clones (pTK- 1 and-2) encoding two distinct isotypes of mouse Mg2+-dependent protein phosphatase β (MPPβ-1 and -2, respectively) were isolated from a melanocyte cDNA library. Although mouse pTK-1 is orthologous to the rat cDNA (JW5) reported previously [Wenk, J., Trompeter, H. I., Pettrich, K. G., Cohen, P. T. W., Campbell, D. G., and Mieskes, G. (1992) FEBS Lett. 297, 135-138], pTK-2 is a novel cDNA clone. It was strongly suggested that the pTK-1 and -2 cDNAs are splicing variants of a single pre-mRNA. The difference in the amino acid sequences between MPPβ-1 and -2 was observed only at the carboxyterminal regions. Both the recombinant MPPβ-1 and -2 expressed in Escherichia coli cells were immunoreactive to an anti-MPPβ antibody and exhibited Mg2+-dependent and okadaic acid-insensitive protein phosphatase activities with similar substrate specificities. Although the mRNA of MPPβ-1 was expressed ubiquitously in various mouse tissues, that of MPPβ-2 was expressed exclusively in brain and heart. These results suggest the difference in the physiological roles of these two enzyme isotypes.

    Original languageEnglish
    Pages (from-to)342-349
    Number of pages8
    JournalArchives of Biochemistry and Biophysics
    Issue number2
    Publication statusPublished - 1993 Jan 1

    ASJC Scopus subject areas

    • Biophysics
    • Biochemistry
    • Molecular Biology


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