H. Takanaga et al., PKN INTERACTS WITH A PARANEOPLASTIC CEREBELLAR DEGENERATION-ASSOCIATED ANTIGEN, WHICH IS A POTENTIAL TRANSCRIPTION FACTOR, Experimental cell research, 241(2), 1998, pp. 363-372
PKN is a fatty acid-activated serine/threonine protein kinase, having
a catalytic domain homologous to protein kinase C family. PKN has been
recently reported to interact with a small GTP-binding protein Rho an
d cytoskeletal proteins such as neurofilament and alpha-actinin. To id
entify the new components of the PKN-signaling pathway, the yeast two-
hybrid system was employed. Using the amino-terminal regulatory domain
of PKN as a bait, cDNA encoding a neural antigen PCD17, which is reco
gnized by characteristic antibodies of patients with paraneoplastic ce
rebellar degeneration, was isolated from a human brain cDNA library. T
he interaction between PKN and PCD17 was also determined by the in vit
ro binding analysis. PCD17 was coimmunoprecipitated with PKN from the
lysate of COS7 cells transfected with both expression constructs for P
KN and the amino-terminal region of PCD17. PCD17 was phosphorylated by
PKN, and the extent of this phosphorylation was enhanced by addition
of 40 mu M arachidonic acid. The amino-terminal region of PCD17 could
form a homodimer in vitro, and PCD17 fused to the Gal4 DNA binding dom
ain showed the transcriptional transactivation of the chloramphenicol
acetyltransferase reporter gene linked to 5 Gal4 binding sites and min
imal promoter in rat C6 glioma cells. These results suggest the partic
ipation of PCD17 in gene expression and lead to a clue for elucidating
the PKN signaling pathway from the cytosol to the nucleus. (C) 1998 A
cademic Press.