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Microtubule affinity-regulating kinase 2 functions downstream of the PAR-3/PAR-6/atypical PKC complex in regulating hippocampal neuronal polarity.

Authors: Chen, Y M  Wang, Q J  Hu, H S  Yu, P C  Zhu, J  Drewes, G  Piwnica-Worms, H  Luo, Z G 
Citation: Chen YM, etal., Proc Natl Acad Sci U S A. 2006 May 30;103(22):8534-9. doi: 10.1073/pnas.0509955103. Epub 2006 May 22.
Pubmed: (View Article at PubMed) PMID:16717194
DOI: Full-text: DOI:10.1073/pnas.0509955103

The PAR-3/PAR-6/atypical PKC (aPKC) complex is required for axon-dendrite specification of hippocampal neurons. However, the downstream effectors of this complex are not well defined. In this article, we report a role for microtubule affinity-regulating kinase (MARK)/PAR-1 in axon-dendrite specification. Knocking down MARK2 expression with small interfering RNAs induced formation of multiple axon-like neurites and promoted axon outgrowth. Ectopic expression of MARK2 caused phosphorylation of tau (S262) and led to loss of axons, and this phenotype was rescued by expression of PAR-3, PAR-6, and aPKC. In contrast, the polarity defects caused by an MARK2 mutant (T595A), which is not responsive to aPKC, were not rescued by the PAR-3/PAR-6/aPKC complex. Moreover, polarity was abrogated in neurons overexpressing a mutant of MARK2 with a deleted kinase domain but an intact aPKC-binding domain. Finally, suppression of MARK2 rescued the polarity defects induced by a dominant-negative aPKC mutant. These results suggest that MARK2 is involved in neuronal polarization and functions downstream of the PAR-3/PAR-6/aPKC complex. We propose that aPKC in complex with PAR-3/PAR-6 negatively regulates MARK(s), which in turn causes dephosphorylation of microtubule-associated proteins, such as tau, leading to the assembly of microtubules and elongation of axons.


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CRRD Object Information
CRRD ID: 13602002
Created: 2018-05-26
Species: All species
Last Modified: 2018-05-26
Status: ACTIVE


RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.