TRIM31 facilitates K27-linked polyubiquitination of SYK to regulate antifungal immunity

Spleen tyrosine kinase(SYK)is a non-receptor tyrosine kinase,which plays an essential role in both innate and adaptive immunity.However,the key molecular mechanisms that regulate SYK activity are poorly understood.Here we identified the E3 ligase TRIM31 as a crucial regulator of SYK activation.We found that TRIM31 interacted with SYK and catalyzed K27-linked polyubiquitination at Lys375 and Lys517 of SYK.This K27-linked polyubiquitination of SYK promoted its plasma membrane translocation and binding with the C-type lectin receptors(CLRs).