Death-associated protein kinase localization to human renal tubule cells, and increased expression of chronic obstructive uropathy in rats.
BACKGROUND
Death-associated protein kinase (DAP kinase) is a Ca2+/calmodulin-dependent serine/threonine kinase implicated as a positive apoptosis mediator. However, little is known about DAP kinase involvement with apoptosis in renal diseases.


METHODS
In order to determine whether DAP kinase has a role in renal cell apoptosis in kidney diseases, we performed an immunohistochemical study using a monoclonal antibody to DAP kinase. Firstly, by examining the cellular distribution of DAP kinase in normal human renal tissues and cultured proximal tubule cells. We then used western blotting and immunohistochemical analysis to examine directly whether DAP kinase protein levels could be modulated in rat kidneys with chronic obstructive uropathy created by unilateral ureteric ligation.


RESULTS
Immunohistochemistry of normal human kidney tissues showed that DAP kinase was exclusively localized in the cytoplasm of renal tubule cells. Expression analysis of DAP kinase using cultured cells confirmed DAP kinase mRNA and protein presence in human renal tubule cells. Immunocytochemical analysis directly visualized DAP kinase in the cytoplasm of the renal tubule cells in culture. Finally, DAP kinase was found up-regulated in renal tubule cells of rat kidneys with chronic obstructive uropathy.


CONCLUSIONS
Our study demonstrates that DAP kinase is localized to renal tubule cells, implying a crucial role for DAP kinase in renal tubular cell apoptosis in progressive renal diseases.
Yukawa
Kazunori
K
Department of Physiology, Wakayama Medical University, Wakayama, Japan. kazu59@wakayama-med.ac.jp
Shirasawa
Nobuyuki
N
Ohshima
Azusa
A
Mune
Masatoshi
M
Kimura
Akihiko
A
Bai
Tao
T
Tsubota
Yuji
Y
Owada-Makabe
Kyoko
K
Tanaka
Tetsuji
T
Kishino
Masanori
M
Tsuruo
Yoshihiro
Y
Umesaki
Naohiko
N
Maeda
Masanobu
M
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D015153:Blotting, Western; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002478:Cells, Cultured; D002908:Chronic Disease; D003593:Cytoplasm / Q000201:enzymology; D064550:Death-Associated Protein Kinases; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007668:Kidney / Q000201:enzymology / Q000473:pathology; D007687:Kidney Tubules, Proximal / Q000201:enzymology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014517:Ureteral Obstruction / Q000201:enzymology* / Q000473:pathology
D051017:Apoptosis Regulatory Proteins; D064550:Death-Associated Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases