Compartmentalized DCC signalling is distinct from DCC localized to lipid rafts.
BACKGROUND
Netrin-1 is a bi-functional cue that attracts or repels different classes of neurons during development. The netrin-1 receptor DCC (deleted in colorectal cancer) acts as a tyrosine kinase-associated receptor to mediate the attractive response towards netrin-1. The lipid raft-localized Src family kinase Fyn is required for DCC-mediated axon guidance. DCC functions are also dependent on lipid rafts, membrane microdomains corresponding to a low-density, detergent-resistant membrane fraction. However, it remains unclear how the association of DCC with lipid rafts controls netrin-1 signalling.


RESULTS
DCC targeted to lipid rafts represented a minor proportion of total DCC inside the cell, but predominated on the cell surface of both IMR-32 human neuroblastoma cells and embryonic cortical neurons. Netrin-1 accumulated in lipid rafts, but had no effect on the targeting of DCC to that compartment, with DCC remaining on the cell surface in lipid rafts through 60 min post-treatment. However, DCC was able to interact with Fyn, both in the lipid rafts and soluble compartments isolated from embryonic E19 rat brains, whereas early downstream signalling components such as Nck-1, and total and active focal adhesion kinase were mainly localized to the non-lipid raft compartment.


CONCLUSIONS
Together, these results suggest that DCC can be found in raft and non-raft portions of the plasma membrane, with early signalling events propagated by non-raft associated DCC.
Petrie
Ryan J
RJ
Department of Anatomy and Cell Biology, McGill University, Quebec, Canada.
Zhao
Beibei
B
Bedford
Fiona
F
Lamarche-Vane
Nathalie
N
D000818:Animals; D001921:Brain / Q000378:metabolism; D045744:Cell Line, Tumor; D000075389:DCC Receptor; D006801:Humans; D021962:Membrane Microdomains / Q000235:genetics / Q000378:metabolism*; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D000075388:Netrin-1; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D051381:Rats; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*
D000075389:DCC Receptor; C501909:DCC protein, human; C501912:Dcc protein, rat; C000617351:NTN1 protein, human; D009414:Nerve Growth Factors; C000617354:Ntn1 protein, rat; D011956:Receptors, Cell Surface; D025521:Tumor Suppressor Proteins; D000075388:Netrin-1