USP44
Description
The USP44 (ubiquitin specific peptidase 44) is a protein-coding gene located on chromosome 12.
Ubiquitin carboxyl-terminal hydrolase 44 is an enzyme that in humans is encoded by the USP44 gene.
USP44 is a deubiquitinase that plays a key regulatory role in the spindle assembly checkpoint, preventing premature anaphase onset. It specifically deubiquitinates CDC20, a negative regulator of the anaphase promoting complex/cyclosome (APC/C), leading to stabilization of the MAD2L1-CDC20-APC/C ternary complex (mitotic checkpoint complex) and preventing premature APC/C activation. This reinforces the spindle assembly checkpoint by promoting MAD2L1 association with CDC20. USP44 also deubiquitinates histones H2A and H2B. It is recruited to RNF8/RNF168-ubiquitinated chromatin surrounding double-stranded breaks, promoting hydrolysis of ubiquitin conjugates and negatively regulating protein recruitment to damaged chromatin. USP44 participates in the nucleotide excision repair (NER) pathway by deubiquitinating DDB2, preventing its premature degradation and allowing it to remain on damaged chromatin. USP44 promotes FOXP3 stabilization through 'Lys-48'-linked deubiquitination, leading to increased stability and regulatory T-cell lineage stability. It also plays a positive role in innate immune response to DNA viruses by deubiquitinating STING1, selectively removing its 'Lys-48'-linked polyubiquitin chains and stabilizing it.
USP44 is also known as -.
