ubiquitin carboxyl-terminal hydrolase 44; deubiquitinating enzyme 44; ubiquitin thiolesterase 44; ubiquitin-specific-processing protease 44 (USP44)

Function

• deubiquitinase
• plays a key role in the spindle checkpoint by preventing premature anaphase onset
• acts by specifically mediating deubiquitination of CDC20, a negative regulator of the anaphase promoting complex (cyclosome, APC/C)
• deubiquitination of CDC20 leads to stabilize the MAD2L1-CDC20-APC/C ternary complex (mitotic checkpoint), thus preventing premature activation of the APC/C
• thiol-dependent hydrolysis of ester, thioester, amide, peptide & isopeptide bonds formed by the C-terminal Gly of ubiquitin
• phosphorylated (probable)
• ubiquitinated; undergoes both Lys-48- & Lys-63-linked polyubiquitination

Structure

• belongs to the peptidase C19 family, USP44 subfamily
• contains 1 UBP-type Zn+2 finger

Compartment

nucleus

Expression

• expressed in testis
• elevated in mitosis
  • levels increase in mitotic cells & rapidly decrease once cells have completed chromosome attachment & exit from mitosis
• induced transcriptionally regulated by POU5F1/OCT4 in embryonic stem cells & embryonal carcinoma cells

More general terms

• ubiquitin C-terminal hydrolase
• nuclear protein
• zinc finger protein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=84101
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:84101
• OMIM: https://mirror.omim.org/entry/610993
• UniProt: http://www.uniprot.org/uniprot/Q9H0E7.html