Molecular cloning of a novel isotype of Mg(2+)-dependent protein phosphatase beta (type 2C beta) enriched in brain and heart.
Two complementary DNA (cDNA) clones (pTK-1 and -2) encoding two distinct isotypes of mouse Mg(2+)-dependent protein phosphatase beta (MPP beta-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 MPP beta-1 and -2 was observed only at the carboxy-terminal regions. Both the recombinant MPP beta-1 and -2 expressed in Escherichia coli cells were immunoreactive to an anti-MPP beta antibody and exhibited Mg(2+)-dependent and okadaic acid-insensitive protein phosphatase activities with similar substrate specificities. Although the mRNA of MPP beta-1 was expressed ubiquitously in various mouse tissues, that of MPP beta-2 was expressed exclusively in brain and heart. These results suggest the difference in the physiological roles of these two enzyme isotypes.
Terasawa
T
T
Department of Biochemistry, Tohoku University, Sendai, Japan.
Kobayashi
T
T
Murakami
T
T
Ohnishi
M
M
Kato
S
S
Tanaka
O
O
Kondo
H
H
Yamamoto
H
H
Takeuchi
T
T
Tamura
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009206:Myocardium / Q000201:enzymology*; D010749:Phosphoprotein Phosphatases / Q000235:genetics* / Q000378:metabolism; D000071636:Protein Phosphatase 2C; D011994:Recombinant Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D007527:Isoenzymes; D011994:Recombinant Proteins; C522359:Mdp1 protein, mouse; D010749:Phosphoprotein Phosphatases; D000071636:Protein Phosphatase 2C