| First Author | Buffington SA | Year | 2012 |
| Journal | Mol Cell Neurosci | Volume | 50 |
| Issue | 1 | Pages | 1-9 |
| PubMed ID | 22445657 | Mgi Jnum | J:196846 |
| Mgi Id | MGI:5490007 | Doi | 10.1016/j.mcn.2012.03.003 |
| Citation | Buffington SA, et al. (2012) IkappaBalpha is not required for axon initial segment assembly. Mol Cell Neurosci 50(1):1-9 |
| abstractText | The inhibitor of NF-kappaB alpha (IkappaBalpha) protein is an important regulator of the transcription factor NF-kappaB. In neurons, IkappaBalpha has been shown to play a role in neurite outgrowth and cell survival. Recently, a phosphorylated form of IkappaBalpha (pIkappaBalpha Ser32/36) was reported to be highly enriched at the axon initial segment (AIS) and was proposed to function upstream of ankyrinG in AIS assembly, including ion channel recruitment. However, we report here that the AIS clustering of ankyrinG and Na(+) channels in the brains of IkappaBalpha knockout (Nfkbia(-/-)) mice is comparable to that in wild-type littermates. Furthermore, we found that multiple phospho-specific antibodies against pIkappaBalpha Ser32/36 non-specifically label AIS in Nfkbia(-/-) cortex and AIS in dissociated Nfkbia(-/-) hippocampal neurons. With the exception of ankyrinG, shRNA-mediated knockdown of known AIS proteins in cultured hippocampal neurons did not eliminate the AIS labeling with pIkappaBalpha antibodies. Instead, the pIkappaBalpha antibodies cross-react with a phosphorylated epitope of a protein associated with the microtubule-based AIS cytoskeleton that is not integrated into the AIS membrane complex organized by ankyrinG. Our results indicate that pIkappaBalpha is neither enriched at the AIS nor required for AIS assembly. |
