MyD88-5 links mitochondria, microtubules, and JNK3 in neurons and regulates neuronal survival.

The innate immune system relies on evolutionally conserved Toll-like receptors (TLRs) to recognize diverse microbial molecular structures. Most TLRs depend on a family of adaptor proteins termed MyD88s to transduce their signals. Critical roles of MyD88-1-4 in host defense were demonstrated by defective immune responses in knockout mice. In contrast, ...
the sites of expression and functions of vertebrate MyD88-5 have remained elusive. We show that MyD88-5 is distinct from other MyD88s in that MyD88-5 is preferentially expressed in neurons, colocalizes in part with mitochondria and JNK3, and regulates neuronal death. We prepared MyD88-5/GFP transgenic mice via a bacterial artificial chromosome to preserve its endogenous expression pattern. MyD88-5/GFP was detected chiefly in the brain, where it associated with punctate structures within neurons and copurified in part with mitochondria. In vitro, MyD88-5 co-immunoprecipitated with JNK3 and recruited JNK3 from cytosol to mitochondria. Hippocampal neurons from MyD88-5-deficient mice were protected from death after deprivation of oxygen and glucose. In contrast, MyD88-5-null macrophages behaved like wild-type cells in their response to microbial products. Thus, MyD88-5 appears unique among MyD88s in functioning to mediate stress-induced neuronal toxicity.
Mesh Terms:
Animals, Cell Compartmentation, Cell Death, Cell Survival, Conserved Sequence, Evolution, Molecular, Glucose, Hippocampus, Mice, Mice, Inbred C57BL, Mice, Knockout, Microtubules, Mitochondria, Mitogen-Activated Protein Kinase 10, Myeloid Cells, Myeloid Differentiation Factor 88, Neurons, Oxygen, Protein Binding, Protein Transport
J. Exp. Med.
Date: Sep. 03, 2007
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