Document Type
Article
Publication Date
7-1-2024
Original Citation
Hanes C,
Mah K,
Steffen D,
McLeod C,
Marcucci C,
Fuller L,
Burgess RW,
Garrett A,
Weiner J.
A C-terminal motif containing a PKC phosphorylation site regulates γ-Protocadherin-mediated dendrite arborization in the cerebral cortex in vivo. Dev Neurobiol. 2024;84(3):217-35.
Keywords
JMG, Animals, Cerebral Cortex, Cadherins, Phosphorylation, Dendrites, Mice, Cadherin Related Proteins, Protein Kinase C, Myristoylated Alanine-Rich C Kinase Substrate, Amino Acid Motifs, Mice, Transgenic
JAX Source
Dev Neurobiol. 2024;84(3):217-35.
ISSN
1932-846X
PMID
38837880
DOI
https://doi.org/10.1002/dneu.22950
Grant
This work was supported by grants to Joshua Weiner and Robert Burgess (NIH R21 NS090030 and NIH R01 NS055272) and to Andrew Garrett (NIH R01 EY031690)
Abstract
The Pcdhg gene cluster encodes 22 γ-Protocadherin (γ-Pcdh) cell adhesion molecules that critically regulate multiple aspects of neural development, including neuronal survival, dendritic and axonal arborization, and synapse formation and maturation. Each γ-Pcdh isoform has unique protein domains—a homophilically interact- ing extracellular domain and a juxtamembrane cytoplasmic domain—as well as a C-terminal cytoplasmic domain shared by all isoforms. The extent to which isoform-specific versus shared domains regulate distinct γ-Pcdh functions remains incompletely understood. Our previous in vitro studies identified protein kinase C (PKC) phosphorylation of a serine residue within a shared C-terminal motif as a mechanism through which γ-Pcdh promotion of dendrite arborization via myris- toylated alanine-rich C-kinase substrate (MARCKS) is abrogated. Here, we used CRISPR/Cas9 genome editing to generate two new mouse lines expressing only non-phosphorylatable γ-Pcdhs, due either to a serine-to-alanine mutation (PcdhgS/A) or to a 15-amino acid C-terminal deletion resulting from insertion of an early stop codon (PcdhgCTD). Both lines are viable and fertile, and the density and maturation of dendritic spines remain unchanged in both PcdhgS/A and PcdhgCTD cortex. Den- drite arborization of cortical pyramidal neurons, however, is significantly increased in both lines, as are levels of active MARCKS. Intriguingly, despite having signifi- cantly reduced levels of γ-Pcdh proteins, the PcdhgCTD mutation yields the strongest phenotype, with even heterozygous mutants exhibiting increased arborization. The present study confirms that phosphorylation of a shared C-terminal motif is a key γ-Pcdh negative regulation point and contributes to a converging understanding of γ-Pcdh family function in which distinct roles are played by both individual isoforms and discrete protein domains.
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