Protein kinase A-dependent phosphorylation of B/K protein.
- Author:
Hemin CHIN
1
;
Sung Ho CHOI
;
Yoon Seong JANG
;
Sung Min CHO
;
Ho Shik KIM
;
Jeong Hwa LEE
;
Seong Whan JEONG
;
In Kyung KIM
;
Grace J KIM
;
Oh Joo KWON
Author Information
1. National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.
- Publication Type:Original Article
- Keywords:
calcium signaling;
phosphorylation;
protein kinase A;
vasopressin
- MeSH:
Sequence Homology, Amino Acid;
Sequence Analysis, DNA;
Rats;
Protein Isoforms/genetics;
Phosphorylation;
Phosphoproteins/genetics/*metabolism;
Molecular Sequence Data;
Mice;
Male;
Humans;
Gene Expression Profiling;
Female;
DNA, Complementary/chemistry/genetics;
Cyclic AMP-Dependent Protein Kinases/*physiology;
Cloning, Molecular;
Cell Line;
Base Sequence;
Animals;
Amino Acid Sequence;
Adult
- From:Experimental & Molecular Medicine
2006;38(2):144-152
- CountryRepublic of Korea
- Language:English
-
Abstract:
We have previously isolated a novel protein "B/K" that contains two C2-like domains. Here, we report the isolatioin and mRNA distribution of a human B/K isoform, and protein kinase A (PKA)-dependent phosphorylation of the B/K protein. The 1.5 kb human B/K cDNA clone exhibits 89% and 97% identities with rat B/K in the sequences of nucleotide and amino acid, respectively. Human B/K isoform encodes a 474 amino acid protein and shows structural features similar to the rat counterpart including two C2 domains, three consensus sequences for PKA, absence of a transmembrane region, and conservation of the N-terminal cysteine cluster. On Northern and dot blot analyses, a 3.0 kb B/K transcript was abundantly present in human brain, kidney, and prostate. Among the brain regions, strong signals were observed in the frontal and temporal lobes, the hippocampus, the hypothalamus, the amygdala, the substantia nigra, and the pituitary. Recombinant B/K proteins containing three consensus sites for PKA was very efficiently phosphorylated in vitro by PKA catalytic subunit. B/K protein which was overexpressed in LLC-PK1 cells was also strongly phosphorylated in vivo by vasopressin analog DDAVP, and PKA-specific inhibitor H89 as well as type 2 vasopressin receptor antagonist specifically suppressed DDAVP-induced B/K phosphorylation. These results suggest that B/K proteins play a role as potential substrates for PKA in the area where they are expressed.
