ubiquitin-activating enzyme E1-like protein 2; monocyte protein 4; MOP-4 (UBE1L2, UBA6, MOP4)

Function

• activates ubiquitin by first adenylating its carboxy-terminal Gly with ATP & linking it to Cys in E1, yielding an ubiquitin-E1 thioester & free AMP
• isoform 2 may play a key role in ubiquitin system & may influence spermatogenesis & male fertility
• role in ubiquitin conjugation, 1st step

Structure

belongs to the ubiquitin-activating E1 family

Alternative splicing

named isoforms=4

Expression

• isoform 2 is predominantly expressed in testis
• higher expression in adult testis than in fetal testis

More general terms

• ligase or synthetase

Database

• UniProt: http://www.uniprot.org/uniprot/A0AVT1.html