Identification and subcellular distribution of endogenous Ins(1,4,5)P(3) 3-kinase B in mouse tissues.
Inositol 1,4,5-trisphosphate 3-kinase (IP(3)-3K) catalyses the phosphorylation of inositol 1,4,5-trisphosphate to inositol 1,3,4,5-tetrakisphosphate. cDNAs encoding three mammalian isoforms have been reported and referred to as IP(3)-3KA, IP(3)-3KB, and IP(3)-3KC. IP(3)-3KB is particularly sensitive to proteolysis at the N-terminus, a mechanism known to generate active fragments of lower molecular mass. Endogenous IP(3)-3KB has therefore not been formally identified in tissues. We have probed a series of murine tissues with an antibody directed against the C-terminus of IP(3)-3KB and used IP(3)-3KB deficient mouse tissues as negative controls. IP(3)-3KB was shown to be particularly well expressed in brain, lung, and thymus with molecular masses of 110-120kDa. The identification of the native IP(3)-3KB by Western blotting for the first time will facilitate further studies of regulation of its activity by specific proteases and/or phosphorylation.
Hascakova-Bartova
Romana
R
Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 808 Route de Lennik, 1070 Brussels, Belgium.
Pouillon
Valérie
V
Dewaste
Valérie
V
Moreau
Colette
C
Jacques
Céline
C
Banting
George
G
Schurmans
Stéphane
S
Erneux
Christophe
C
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology*; D019556:COS Cells; D002522:Chlorocebus aethiops; D008168:Lung / Q000201:enzymology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009928:Organ Specificity; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000201:enzymology*; D013950:Thymus Gland / Q000201:enzymology*; D014018:Tissue Distribution
D011994:Recombinant Proteins; D017853:Phosphotransferases (Alcohol Group Acceptor); C051038:Inositol 1,4,5-trisphosphate 3-kinase