First published online April 3, 2008
Journal of Cell Science 121, 801e (2008)
© The Company of Biologists Limited
Making and breaking cell-cell contacts
The transmembrane proteins CD47 and SHPS-1 can interact specifically via their respective extracellular domains, leading to the direct association of CD47- and SHPS-1-expressing cells. Although cell-to-cell communication via CD47 and SHPS-1 has a role in diverse processes, including the formation of neurites on neurons, how the CD47–SHPS-1 interaction is regulated is unknown. On page 1213, Takashi Matozaki and colleagues use two populations of CHO cells, which express either CD47 or SHPS-1, to investigate the regulation of the CD47–SHPS-1 system. The authors show that the association of the two proteins, and hence the two cell types, causes the trans-endocytic uptake of CD47 into SHPS-1-expressing cells (SHPS-1 is also trans-endocytosed by CD47-expressing cells, but to a lesser extent). The authors show that the trans-endocytosis of CD47 is mediated by clathrin and dynamin, and requires the juxtamembrane region of SHPS-1. After trans-endocytosis, CD47 colocalises with SHPS-1 in multivesicular bodies, implying that the two proteins are trans-endocytosed together and are subsequently degraded within lysosomes. Importantly, inhibiting the trans-endocytosis of CD47 stimulates the aggregation of CD47- and SHPS-1-expressing cells. The authors conclude that the trans-endocytosis of CD47 is a key regulator of the CD47–SHPS-1 system.
Related articles in JCS:
- Trans-endocytosis of CD47 and SHPS-1 and its role in regulation of the CD47–SHPS-1 system
- Shinya Kusakari, Hiroshi Ohnishi, Feng-Jie Jin, Yuka Kaneko, Takaaki Murata, Yoji Murata, Hideki Okazawa, and Takashi Matozaki
JCS 2008 121: 1213-1223.
[Abstract]
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