%0 Journal Article
%T Study on intracellular trafficking of Mac-1 by direct visualization
%A YAN Ming
%A MAO Jifang
%A WEI Yi
%A ZHONG Jigen
%A YANG Shengsheng
%A XU Renbao
%A <br>YAN Ming
%A MAO Jifang
%A WEI Yi
%A ZHONG Jigen
%A YANG Shengsheng & XU Renbao .
%J 中国科学C辑(英文版)
%D 2004
%I Springer
%X Previously, we constructed DNA vectors containing cDNA of Mac-1 subunits (CD11b or CD18b) fused with fluorescence protein (FP). cDNA fragments and the DNA constructs were then transfected into CHO cells (as CHO-Mac-1-FP). The structure and function of Mac-1-FP obtained from the CHO-Mac-1-FP cells are nearly identical to that expressed in wild type leukocytes. In the present study, the intracellular trafficking of Mac-1 was visualized directly by monitoring the fluorescent intensities of YFP-CD18 and PE-conjugated monoclonal antibody against CD11b under a confocal microscope in CHO-Mac-1-FP cells. The results indicate that: (i) although Mac-1 was not detected in the cell membrane at resting state, it had been translocated and clustered into the cell membrane by 1 h and internalized 2 h after PMA stimulation, at which point the fluorescence intensity began to diminish gradually, probably due to partial degradation of Mac-1. The fluorescence of CD18 and CD11b reappeared on the cell membrane 1 h after re-treatment with PMA, suggesting the recycling of non-degraded Mac-1. (ii) The adhesion rate of CHO-Mac-1-FP to magnetic beads coupled ICAM-1 increased within 4 h after their initial interaction, accompanied by the clustering of Mac-1-FP. After 8 h, the adhesion rate declined and fluorescence also decreased simultaneously. The pattern of change in fluorescence in CHO-Mac-1-FP cells elicited by ICAM-1 beads was similar to that elicited by PMA, suggesting that endocytosis and degradation of Mac-1 occurred after the interaction with ICAM-1. Thus, we conclude that the intracellular trafficking of Mac-1 after activation is associated with membrane translocation, endocytosis, degradation and recycling. These changes are in parallel with the adhesion of CHO-Mac-1-FP cells with ICAM-1, and may be involved in the adhesion and detachment of leukocytes. The detachment of leukocytes may be caused by endocytosis of Mac-1.
%K Mac-1 (macrophage differentiation antigen associated with complement three receptor function)
%K PMA
%K ICAM-1
%K trafficking<br>
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=90BA3D13E7F3BC869AC96FB3DA594E3FE34FBF7B8BC0E591&jid=180CF3A72E750F3261A8A60EDC957784&aid=A25EBC376EF01730F5F706B91D557E6C&yid=D0E58B75BFD8E51C&vid=F4B561950EE1D31A&iid=B31275AF3241DB2D&sid=68FF5306A8F9C315&eid=2A2AA8B7E19F0DF7&journal_id=1674-7305&journal_name=ScienceChina.Lifesciences&referenced_num=0&reference_num=15