Molecular cloning and expression of mouse mg2+-dependent protein phosphatase β-4 (Type 2Cβ-4)

Shunsuke Kato, Takayuki Terasawa, Takayasu Kobayashi, Motoko Ohnishi, Yoji Sasahara, Kazuyuki Kusuda, Yuchio Yanagawa, Akira Hiraga, Yasuhisa Matsui, Shinri Tamura

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


A full-length complementary DNA (cDNA) clone (pTK-3) encoding an isoform of Mg2+-dependent protein phosphatase β (MPPβ-4) was isolated for the first time from a mouse melanocyte cDNA library. It was strongly suggested that the mRNA corresponding to the pTK-3 insert was a splicing variant of a single pre-mRNA that also encodes MPPβ-1 and -2 (T. Terasawa, T. Kobayashi, T. Murakami, M. Ohnishi, S. Kato, O. Tanaka, H. Kondo, H. Yamamoto, T. Takeuchi, and S. Tamura, 1993, Arch. Biochem. Biophys. 307, 342-349). The amino acid sequence of MPPβ-4 differed from those of MPPβ-1 and -2 only at the carboxyl terminal region. Analysis by reverse transcriptase polymerase chain reaction (RT-PCR) revealed that MPPβ-4 mRNA was expressed only in testis and intestine and not in other mouse tissues tested. Specific expression of the mRNA signals of two other isoforms of MPPβ, MPPβ-3 and -5 (a novel isoform), in testis and intestine was also demonstrated by the RT-PCR. The carboxyl terminal region of MPPβ-5 was found to have a chimera structure composed of part of MPPβ-1 and part of MPPβ-3. The recombinant MPPβ-3 and -4 and the putative MPPβ-5 expressed in Escherichia coli cells exhibited Mg2+-dependent and okadaic acid-insensitive protein phosphatase activities. It was demonstrated that the mRNA expression levels of MPPβ-3, -4, and -5 alter according to the maturation of mouse testis. These resuits suggest that the complex structure of MPPβ isoforms and their tissue- and developmental stage-specific expression reflect the variety of their physiological functions.

Original languageEnglish
Pages (from-to)387-393
Number of pages7
JournalArchives of Biochemistry and Biophysics
Issue number2
Publication statusPublished - 1995 Apr 20


  • CDNA cloning
  • Expression vector
  • Molecular diversity
  • Protein phosphatase
  • Tissue-specific expression

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology


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