Thymosin beta4 is involved in stabilin-2-mediated apoptotic cell engulfment.
Stabilin-2 was recently identified as a novel receptor for membrane phosphatidylserine of apoptotic cells. To identify proteins that were candidates for stabilin-2 cytoplasmic domain binding, we screened a human spleen cDNA library using the yeast two-hybrid system. We found that thymosin beta4 interacts with the stabilin-2 cytoplasmic domain and is co-localized with stabilin-2 at the phagocytic cup. Knockdown of thymosin beta4 significantly decreased the phagocytic activity of stabilin-2, whereas overexpression of thymosin beta4 increased this activity. Additionally, amino acids 2504-2514 of stabilin-2 cytoplasmic domain were found to be responsible for the interaction with thymosin beta4. Taken together, these results suggest that thymosin beta4 is a downstream molecule of stabilin-2 that plays a role in stabilin-2-mediated cell corpse clearance.
Cell and Matrix Research Institute, Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.
Sung-Jin
SJ
Lee
In-Seop
IS
So
Seung-Yoon
SY
Park
In-San
IS
Kim
D000595:Amino Acid Sequence; D017209:Apoptosis; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D015723:Gene Library; D006801:Humans; D008969:Molecular Sequence Data; D010587:Phagocytosis; D013947:Thymosin / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D000099201:Thymosin beta(4)
D015816:Cell Adhesion Molecules, Neuronal; D013947:Thymosin; D000099201:Thymosin beta(4); C449927:STAB2 protein, human