Expression and Properties of Two Types of Protein Kinase C: Alternative Splicing from a Single Gene

Abstract

Two complementary DNA's, encoding the complete sequences of 671 and 673 amino acids for subspecies of rat brain protein kinase C, were expressed in COS 7 cells. The complementary DNA sequence analysis predicted that the two enzymes are derived from different ways of splicing and differ from each other only in the short ranges of their carboxyl-terminal regions. Both enzymes showed typical characteristics of protein kinase C that responded to Ca2+, phospholipid, and diacylglycerol. The enzymes showed practically identical physical and kinetic properties and were indistinguishable from one of the several subspecies of protein kinase C that occurs in rat brain but not in untransfected COS 7 cells. Partial analysis of the genomic structure confirmed that these two subspecies of protein kinase C resulted indeed from alternative splicing of a single gene.

Specific protein kinase C isoforms as transducers and modulators of insulin signaling

“…These early studies relied upon chromatographic elution profiles and specific activation by phospholipids, diacylglycerol and calcium [72][73][74][75]. In some cases, phorbol ester desensitization was taken as an indication of a role for specific PKC isoforms in insulin action [76].…”

“…When objective sequence alignments are carried out, five variable regions within the conventional PKC gene encode isoform specificity [78,79]. The last variable region (V5) of PKCβ consists of 50-52 amino acids that are alternatively spliced and results in transcripts encoding two proteins [74,80]. The regulation of exon inclusion by insulin produces PKCβII which further contributes to full effects on insulin signaling as shown with experiments that alter splicing, inhibit PKCβII activity, down-regulate PKCβII levels and overexpression of the active isoform [42,81,82].…”

New PKCδ family members, PKCδIV, δV, δVI, and δVII are specifically expressed in mouse testis

“…PKCdVI and dVII had a new V5 sequence at their C-terminus, indicating that the last exon of PKCdVI and dVII was replaced with a new exon as the V5 domain. It was reported that PKCbI and bII were produced by alternative splicing of the C-terminal last exon of the V5 domain [2]. The V5 domain of PKCbI and bII may function in intracellular localization [32,33] and various physiological roles [34][35][36].…”

“…Members of the PKC family are divided into three groups based on their molecular structures and activating mechanisms: (i) conventional PKC (a, b, and c isoforms) requiring calcium, phosphatidylserine (PS), and diacylglycerol (DG) for activation; (ii) novel PKC (d, e, g, and h isoforms) activated independently of calcium; and (iii) atypical PKC (f and k/i isoforms), which are independent of both calcium and DG for activation. Alternative splicing-derived variants of PKC have been reported for the b, d, h, and f isoforms, i.e., PKCbII [2], PKCdII [3], PKCdIII [4], PKChII [5], and fII [6].…”

Cloning and expression of a cDNA encoding a novel human neurotrophic factor

“…The 1.1. kb EcoRI fragment of human NGF-2 cDNA prepared from AHNT31 was inserted downstream of the LTR region of Abelson murine leukemia virus and the SV40 promoter in the expression plasmid [14] to give pNTL145. The conditioned medium of COS-7 cells transfected with the plasmid pNTL145 supported the survival of sensory neurons of chicken E8 dorsal root ganglia (Fig.…”