The Drosophila cell adhesion molecule Klingon is required for long-term memory formation and is regulated by Notch

Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu, Tokyo 183-8526, Japan.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 01/2009; 106(1):310-5. DOI: 10.1073/pnas.0807665106
Source: PubMed


The ruslan (rus) mutant was previously identified in a behavioral screen for mutants defective in long-lasting memory, which consists of two consolidated memory types, anesthesia-resistant memory, and protein synthesis-dependent long-term memory (LTM). We demonstrate here that rus is a new allele of klingon (klg), which encodes a homophilic cell adhesion molecule. Klg is acutely required for LTM but not anesthesia-resistant memory formation, and Klg expression increases upon LTM induction. LTM formation also requires activity of the Notch cell-surface receptor. Although defects in Notch have been implicated in memory loss because of Alzheimer's disease, downstream signaling linking Notch to memory have not been determined. Strikingly, we found that Notch activity increases upon LTM induction and regulates Klg expression. Furthermore, Notch-induced enhancement of LTM is disrupted by a klg mutation. We propose that Klg is a downstream effector of Notch signaling that links Notch activity to memory.

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    • "Interestingly, the study also showed that over-expression of Su(H) protein in the wild-type background caused LTM defects (Song et al., 2009). Another study has identified the homotypic cell adhesion molecule Klingon as functioning downstream of Notch in LTM (Matsuno et al., 2009), but it’s not clear whether it is regulated by NICD. Thus, data from both mice and Drosophila raise doubts about the involvement of canonical Notch signaling in LTM. "
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    ABSTRACT: Notch is a cell surface receptor that is well known to mediate inter-cellular communication during animal development. Data in the field indicate that it is also involved in the formation of long-term memory (LTM) in the fully developed adults and in memory loss upon neurodegeneration. Our studies in the model organism Drosophila reveal that a non-canonical Notch-protein kinase C activity that plays critical roles in embryonic development also regulates cyclic-AMP response element binding protein during LTM formation in adults. Here we present a perspective on how the various known features of Notch function relate to LTM formation and how they might interface with elements of Wingless/Wnt signaling in this process.
    Full-text · Article · Nov 2013 · Frontiers in Cellular Neuroscience
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    • "Several studies implicate Notch signaling in adult synaptic plasticity, learning, and memory [reviewed in (Costa, Drew, & Silva, 2005)]. For instance, increasing Notch function enhances long-term memory formation, whereas disrupting Notch inhibits memory formation in Drosophila across several paradigms (Ge et al., 2004; Matsuno, Horiuchi, Tully, & Saitoe, 2009; Presente, Boyles, Serway, de Belle, & Andres, 2004). Consistent with this, long-term potentiation (LTP), argued to be a cellular correlate of memory formation, is impaired in mice with reduced Notch1 protein in the hippocampus [produced by expressing antisense directed against Notch1 mRNA] (Wang et al., 2004). "
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    ABSTRACT: It is well-known that Notch signaling plays a critical role in brain development and growing evidence implicates this signaling pathway in adult synaptic plasticity and memory formation. The Notch1 receptor is activated by two subclasses of ligands, Delta-like (including Dll1 and Dll4) and Jagged (including Jag1 and Jag2). Ligand-induced Notch1 receptor signaling is modulated by a family of Fringe proteins, including Lunatic fringe (Lfng). Although Dll1, Jag1 and Lfng are critical regulators of Notch signaling, their relative contribution to memory formation in the adult brain is unknown. To investigate the roles of these important components of Notch signaling in memory formation, we examined spatial and fear memory formation in adult mice with reduced expression of Dll1, Jag1, Lfng and Dll1 plus Lfng. We also examined motor activity, anxiety-like behavior and sensorimotor gating using the acoustic startle response in these mice. Of the lines of mutant mice tested, we found that only mice with reduced Jag1 expression (mice heterozygous for a null mutation in Jag1, Jag1(+/-)) showed a selective impairment in spatial memory formation. Importantly, all other behavior including open field activity, conditioned fear memory (both context and discrete cue), acoustic startle response and prepulse inhibition, was normal in this line of mice. These results provide the first in vivo evidence that Jag1-Notch signaling is critical for memory formation in the adult brain.
    Full-text · Article · Jul 2013 · Neurobiology of Learning and Memory
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    • "A third mutant, D0417, is within the Klingon (Klg) gene that encodes a member of the immunoglobulin superfamily of cell adhesion molecules and has also been implicated in photoreceptor development (Butler et al., 1997). Klg has been shown to be acutely required for LTM and regulated by Notch (Matsuno et al., 2009). Oskar is involved in the translocation of mRNA to the posterior pole during oocyte development and assembly of the germ plasm (Ephrussi and Lehmann, 1992; Lehmann and Ephrussi, 1994). "
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    ABSTRACT: A prior screen identified dozens of Drosophila melanogaster mutants that possess defective long-term memory (LTM). Using spaced olfactory conditioning, we trained 26 of these mutant lines to associate an odor cue with electric shock and then examined the memory of this conditioning 24 h later. All of the mutants tested revealed a deficit in LTM compared to the robust LTM observed in control flies. We used in vivo functional optical imaging to measure the magnitude of a previously characterized LTM trace, which is manifested as increased calcium influx into the axons of α/β mushroom body neurons in response to the conditioned odor. This memory trace was defective in all 26 of the LTM mutants. These observations elevate the significance of this LTM trace given that 26 independent mutants all exhibit a defect in the trace, and further suggest that the calcium trace is a fundamental mechanism underlying Drosophila LTM.
    Preview · Article · Apr 2011 · The Journal of Neuroscience : The Official Journal of the Society for Neuroscience
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