Premium
Inactive forms of the catalytic subunit of protein kinase A are expressed in the brain of higher primates
Author(s) -
Larsen Anja C. V.,
Kvissel AnneKatrine,
Hafte Tilahun T.,
Avellan Cecilia I. A.,
Eikvar Sissel,
Rootwelt Terje,
Ørstavik Sigurd,
Skålhegg Bjørn S.
Publication year - 2008
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2007.06195.x
Subject(s) - protein subunit , alternative splicing , exon , protein kinase a , splice , immunoprecipitation , rna splicing , microbiology and biotechnology , gene , biology , messenger rna , kinase , gene expression , biochemistry , rna
It is well documented that the β‐gene of the catalytic (C) subunit of protein kinase A encodes a number of splice variants. These splice variants are equipped with a variable N‐terminal end encoded by alternative use of several exons located 5′ to exon 2 in the human, bovine and mouse Cβ gene. In the present study, we demonstrate the expression of six novel human Cβ mRNAs that lack 99 bp due to loss of exon 4. The novel splice variants, designated CβΔ4, were identified in low amounts at the mRNA level in NTera2‐N cells. We developed a method to detect CβΔ4 mRNAs in various cells and demonstrated that these variants were expressed in human and Rhesus monkey brain. Transient expression and characterization of the CβΔ4 variants demonstrated that they are catalytically inactive both in vitro against typical protein kinase A substrates such as kemptide and histone, and in vivo against the cAMP‐responsive element binding protein. Furthermore, co‐expression of CβΔ4 with the regulatory subunit (R) followed by kinase activity assay with increasing concentrations of cAMP and immunoprecipitation with extensive washes with cAMP (1 m m ) and immunoblotting demonstrated that the CβΔ4 variants associate with both RI and RII in a cAMP‐independent fashion. Expression of inactive C subunits which associate irreversibly with R may imply that CβΔ4 can modulate local cAMP effects in the brain by permanent association with R subunits even at saturating concentrations of cAMP.