Ryuji Sato, Hiroshi Ohnishi, Hisae Kobayashi, Daisuke Kiuchi, Akiko Hayashi, Yuka Kaneko, Nakayuki Honma, Hideki Okazawa, Yukio Hirata, Takashi Matozaki
Biosignal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-Machi, Maebashi, Gunma 371-8512, Japan.
Biochemical and biophysical research communications 2003 Sep 26SHPS-1 is a receptor-type transmembrane glycoprotein, which contains four tyrosine residues in its cytoplasmic region, and the phosphorylation of these tyrosine residues serves the binding sites for SHP-2 protein-tyrosine phosphatase. Its extracellular region interacts with another membrane protein, CD47, thereby constituting a cell-cell communication system. We analyzed this ligand-receptor interaction using Chinese hamster ovary (CHO) cells expressing wild-type (WT) or mutant SHPS-1. The binding affinity of an SHPS-1 mutant such as deltaCyto, that lacked most of cytoplasmic region, or 4F, in which all four tyrosine residues in cytoplasmic region were substituted with phenylalanine, for a recombinant CD47-Fc was greater than that of WT. In addition, oligomerization of deltaCyto or 4F mutant by binding of CD47-Fc was greater than WT. Chemical cross-linking of SHPS-1 indicated that SHPS-1 formed a cis-dimer. Furthermore, WT cells exhibited a less polarized cell shape with decreased formation of actin stress fibers, compared with parental CHO cells and mutant SHPS-1 expressing cells. Prominent lamellipodium formation and membrane ruffling were also observed at leading edges of migrating WT cells but not at those of other mutant SHPS-1 expressing cells. These results suggest that the binding affinity of SHPS-1 to CD47, clustering ability of SHPS-1, and cytoskeletal reorganization are regulated by the cytoplasmic region of SHPS-1.
Ryuji Sato, Hiroshi Ohnishi, Hisae Kobayashi, Daisuke Kiuchi, Akiko Hayashi, Yuka Kaneko, Nakayuki Honma, Hideki Okazawa, Yukio Hirata, Takashi Matozaki. Regulation of multiple functions of SHPS-1, a transmembrane glycoprotein, by its cytoplasmic region. Biochemical and biophysical research communications. 2003 Sep 26;309(3):584-90
PMID: 12963030
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