Kalirin-7, a protein enriched in postsynaptic density, is involved in ischemic signal transduction.
Regulators of mitogen activated protein kinases (MAPK) and c-Jun N-terminal/stress-activated kinase (JNK) include Rho-like small GTP-binding proteins and their regulators. SynGAP and kalirin-7 are postsynaptic density-enriched proteins identified through their interaction with Rho GTPases and PSD-95 scaffold protein. We examined immunoreactivity of SynGAP, kalirin-7, and PSD-95, phosphorylation of MAPK and JNK in control and postischemic hippocampus in gerbil model of transient forebrain ischemia. In normal brain higher amount of kalirin-7 but a lower amount of P-JNK was found in ischemia-resistant hippocampal area: CA2-3, DG than in ischemia-vulnerable CA1. After 5 min ischemia and 1 h reperfusion a decrease of P-ERK and increase of P-JNK were uniformly observed in the hippocampal parts. By contrast, the amount of kalirin-7 in CA2-3, DG reached 56% (P < 0.001) of control while was doubled in CA1. Oppositely, the immunoreactivity of SynGAP was increased in CA2-3, DG and reduced in CA1. Our data indicate that SynGAP and kalirin-7 take part in the regulation of ischemic signal transduction but the mechanism does not seem directly connected with the activation of MAPK and JNK.
Beresewicz
Małgorzata
M
Molecular Biology Unit, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego St., 02-106, Warsaw, Poland.
Kowalczyk
Joanna E
JE
Zabłocka
Barbara
B
D000818:Animals; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000378:metabolism; D005849:Gerbillinae; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism; D007511:Ischemia / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D009419:Nerve Tissue Proteins; C033652:postsynaptic density proteins; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases