PDZK1 prevents neointima formation via suppression of breakpoint cluster region kinase in vascular smooth muscle.

Wan Ru Lee, Anastasia Sacharidou, Erica Behling-Kelly, Sarah C Oltmann, Weifei Zhu, Mohamed Ahmed, Robert D Gerard, David Y Hui, Jun-ichi Abe, Philip W Shaul, Chieko Mineo

PloS one 2015

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Scavenger receptor class B, type I (SR-BI) and its adaptor protein PDZK1 mediate responses to HDL cholesterol in endothelium. Whether the receptor-adaptor protein tandem serves functions in other vascular cell types is unknown. The current work determined the roles of SR-BI and PDZK1 in vascular smooth muscle (VSM). To evaluate possible VSM functions of SR-BI and PDZK1 in vivo, neointima formation was assessed 21 days post-ligation in the carotid arteries of wild-type, SR-BI-/- or PDZK1-/- mice. Whereas neointima development was negligible in wild-type and SR-BI-/-, there was marked neointima formation in PDZK1-/- mice. PDZK1 expression was demonstrated in primary mouse VSM cells, and compared to wild-type cells, PDZK1-/- VSM displayed exaggerated proliferation and migration in response to platelet derived growth factor (PDGF). Tandem affinity purification-mass spectrometry revealed that PDZK1 interacts with breakpoint cluster region kinase (Bcr), which contains a C-terminal PDZ binding sequence and is known to enhance responses to PDGF in VSM. PDZK1 interaction with Bcr in VSM was demonstrated by pull-down and by coimmunoprecipitation, and the augmented proliferative response to PDGF in PDZK1-/- VSM was abrogated by Bcr depletion. Furthermore, compared with wild-type Bcr overexpression, the introduction of a Bcr mutant incapable of PDZK1 binding into VSM cells yielded an exaggerated proliferative response to PDGF. Thus, PDZK1 has novel SR-BI-independent function in VSM that affords protection from neointima formation, and this involves PDZK1 suppression of VSM cell proliferation via an inhibitory interaction with Bcr.

Citation

Wan Ru Lee, Anastasia Sacharidou, Erica Behling-Kelly, Sarah C Oltmann, Weifei Zhu, Mohamed Ahmed, Robert D Gerard, David Y Hui, Jun-ichi Abe, Philip W Shaul, Chieko Mineo. PDZK1 prevents neointima formation via suppression of breakpoint cluster region kinase in vascular smooth muscle. PloS one. 2015;10(4):e0124494