Thymosin β4 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 β4 interacts with the stabilin-2 cytoplasmic domain and is co-localized with stabilin-2 at the phagocytic cup. Knockdown of thymosin β4 significantly decreased the phagocytic activity of stabilin-2, whereas overexpression of thymosin β4 increased this activity. Additionally, amino acids 2504–2514 of stabilin-2 cytoplasmic domain were found to be responsible for the interaction with thymosin β4. Taken together, these results suggest that thymosin β4 is a downstream molecule of stabilin-2 that plays a role in stabilin-2-mediated cell corpse clearance.Structured summaryMINT-6542321, MINT-6542357:Stab2-c (uniprotkb:Q8WWQ8) physically interacts (MI:0218) with tb4 (uniprotkb:P20065) by anti tag coimmunoprecipitation (MI:0007)MINT-6542368:Stab2-c (uniprotkb:Q8WWQ8) physically interacts (MI:0218) with tb4 (uniprotkb:P20065) by pull down (MI:0096)MINT-6542300:Stab2-c (uniprotkb:Q8WWQ8) physically interacts (MI:0218) with tb4 (uniprotkb:P62328) by two hybrid (MI:0018)