The unique prodomain of T-cadherin plays a key role in adiponectin binding with the essential extracellular cadherin repeats 1 and 2.
Adiponectin, an adipocyte-derived circulating protein, accumulates in the heart, vascular endothelium, and skeletal muscles through an interaction with T-cadherin (T-cad), a unique glycosylphosphatidylinositol-anchored cadherin. Recent studies have suggested that this interaction is essential for adiponectin-mediated cardiovascular protection. However, the precise protein-protein interaction between adiponectin and T-cad remains poorly characterized. Using ELISA-based and surface plasmon analyses, we report here that T-cad fused with IgG Fc as a fusion tag by replacing its glycosylphosphatidylinositol-anchor specifically bound both hexameric and larger multimeric adiponectin with a dissociation constant of ∼1.0 nm and without any contribution from other cellular or serum factors. The extracellular T-cad repeats 1 and 2 were critical for the observed adiponectin binding, which is required for classical cadherin-mediated cell-to-cell adhesion. Moreover, the 130-kDa prodomain-bearing T-cad, uniquely expressed on the cell surface among members of the cadherin family and predominantly increased by adiponectin, contributed significantly to adiponectin binding. Inhibition of prodomain-processing by a prohormone convertase inhibitor increased 130-kDa T-cad levels and also enhanced adiponectin binding to endothelial cells both by more preferential cell-surface localization and by higher adiponectin-binding affinity of 130-kDa T-cad relative to 100-kDa T-cad. The preferential cell-surface localization of 130-kDa T-cad relative to 100-kDa T-cad was also observed in normal mice aortain vivoIn conclusion, our study shows that a unique key feature of the T-cad prodomain is its involvement in binding of the T-cad repeats 1 and 2 to adiponectin and also demonstrates that adiponectin positively regulates T-cad abundance.
From the Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
Shiro
S
Fukuda
From the Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan, shunkita@endmet.med.osaka-u.ac.jp.|the Department of Metabolism and Atherosclerosis, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan, and.
Shunbun
S
Kita
From the Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
Yoshinari
Y
Obata
From the Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
Yuya
Y
Fujishima
From the Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
Hirofumi
H
Nagao
From the Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
Shigeki
S
Masuda
From the Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
Yoshimitsu
Y
Tanaka
From the Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
Hitoshi
H
Nishizawa
From the Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.|the Department of Metabolism and Atherosclerosis, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan, and.
Tohru
T
Funahashi
the Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan.
Junichi
J
Takagi
From the Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.|the Department of Metabolism and Atherosclerosis, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan, and.
Norikazu
N
Maeda
From the Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
Iichiro
I
Shimomura
D052242:Adiponectin / Q000737:chemistry* / Q000235:genetics; D000818:Animals; D016466:CHO Cells; D015820:Cadherins / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry; D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D004220:Disulfides / Q000737:chemistry; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D017261:Glycosylphosphatidylinositols / Q000737:chemistry; D057809:HEK293 Cells; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry; D007700:Kinetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011485:Protein Binding; D000072417:Protein Domains; D025941:Protein Interaction Mapping; D020349:Surface Plasmon Resonance
D052242:Adiponectin; D015820:Cadherins; D004220:Disulfides; D017261:Glycosylphosphatidylinositols; C099972:H-cadherin; D007074:Immunoglobulin G; D002118:Calcium
adipokine; adiponectin; cadherin; cell surface protein; glycosylphosphatidylinositol (GPI anchor); protein domain; protein-protein interaction