Scavenger receptor CL-P1 mediates endocytosis by associating with AP-2μ2

• Published in: Biochimica et biophysica acta Vol. 1840; no. 11; pp. 3226 - 3237
• Main Authors: Jang, SeongJae, Ohtani, Katsuki, Fukuoh, Atsushi, Mori, Kenichiro, Yoshizaki, Takayuki, Kitamoto, Noritoshi, Kim, YounUck, Suzuki, Yasuhiko, Wakamiya, Nobutaka
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2014
• Subjects: Adaptor complex; cDNA libraries; clathrin; Collectin; complementary DNA; dynamins; Endocytosis; endothelial cells; ligands; microorganisms; Scavenger Receptors; site-directed mutagenesis; two hybrid system techniques; tyrosine; Tyrosine motif; Tyrosine motif; Endocytosis; Collectin; Adaptor complex; Scavenger Receptors
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2014.07.019

Scavenger receptor CL-P1 (collectin placenta 1) has been found recently as a first membrane-type collectin which is mainly expressed in vascular endothelial cells. CL-P1 can endocytose OxLDL as well as microbes but in general, the endocytosis mechanism of a scavenger receptor is not well elucidated. We screened a placental cDNA library using a yeast two-hybrid system to detect molecules associated with the cytoplasmic domain of CL-P1. We analyzed the binding and endocytosis of several ligands in CL-P1 transfectants and performed the inhibition study using tyrphostin A23 which is a specific inhibitor of tyrosine kinase, especially in μ2-dependent endocytosis and the site-directed mutagenesis in the endocytosis YXXΦ motif in CL-P1 cytoplasmic region. Furthermore, the SiRNA study of clathrin, adaptor AP-2 and dynamin-2 during the endocytosis of OxLDL in CL-P1 transfectant cells was carried out. We identified μ2 subunit of the AP-2 adaptor complex as a molecule associated with the cytoplasmic region of CL-P1. We demonstrated that AP-2μ2 was essential for CL-P1 mediated endocytosis of OxLDL in CL-P1 transfectant cells and its endocytosis was also mediated by clathrin, dynamin and adaptin complex molecules. Tyrosine-based YXXΦ sequences play an important role in CL-P1-mediated OxLDL endocytosis associated with AP-2μ2. This might be the first finding of the clear endocytosis mechanism in scavenger receptor CL-P1. •We identified AP-2μ2 as a molecule associated with the cytoplasmic region of CL-P1.•AP-2μ2 was essential for CL-P1 mediated endocytosis in CL-P1 transfectants.•YXXΦ sequences associated with AP-2μ2 play an important role in OxLDL endocytosis.•The endocytosis due to CL-P1 was mediated by clathrin, dynamin and adaptin proteins.