Identification of regulated genes during permanent focal cerebral ischaemia: characterization of the protein kinase 9b5/MARKL1/MARK4.
Cerebral ischaemia induces transcriptional changes in a number of pathophysiologically important genes. Here we have systematically studied gene expression changes after 90 min and 24 h of permanent focal ischaemia in the mouse by an advanced fragment display technique (restriction-mediated differential display). We identified 56 transcriptionally altered genes, many of which provide novel hints to ischaemic pathophysiology. Particularly interesting were two pro-apoptotic genes (Grim19 and Tdag51), whose role in cerebral ischaemia and neuronal cell death has not been recognized so far. Among the unknown sequences, we identified a gene that was rapidly and transiently up-regulated. The encoded protein displayed high homology to the MARK family of serine-threonine protein kinases and has recently been described as MARKL1/MARK4. Here we demonstrate that this protein is a functional protein kinase with the ability to specifically phosphorylate a cognate peptide substrate for the AMP-kinase family. Upon overexpression in heterologous cells, the functional wild-type protein, but not its kinase-dead mutant, led to decreased cell viability. We conclude that the up-regulation of this kinase during focal ischaemia may represent an interesting new target for pharmacological intervention.
Axaron Bioscience AG, Heidelberg, Germany. schneider@axaron.de
Armin
A
Schneider
Rico
R
Laage
Oliver
O
von Ahsen
Achim
A
Fischer
Moritz
M
Rossner
Sigrid
S
Scheek
Sylvia
S
Grünewald
Rohini
R
Kuner
Daniela
D
Weber
Carola
C
Krüger
Bettina
B
Klaussner
Bernhard
B
Götz
Holger
H
Hiemisch
Dieter
D
Newrzella
Ana
A
Martin-Villalba
Alfred
A
Bach
Markus
M
Schwaninger
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D002545:Brain Ischemia / Q000201:enzymology* / Q000235:genetics*; D002470:Cell Survival / Q000235:genetics; D003001:Cloning, Molecular; D004195:Disease Models, Animal; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D017385:Sequence Homology; D017386:Sequence Homology, Amino Acid
C111833:MARK3 protein, human; C482979:MARK4 protein, mouse; D017346:Protein Serine-Threonine Kinases