PICOT: A Multidomain Protein with Multiple Functions

The PICOT protein possesses three highly conserved regions that include an aminoterminal thioredoxin-like homology domain and a tandem repeat of a carboxyterminal PICOT homology domain with an overall conformation that resembles a glutaredoxin homology domain. In contrast to the classical dithiol thioredoxins and glutaredoxins, PICOT possesses a single cysteine residue in each of its three domains and is therefore distinct from the classical thioredoxin and glutaredoxin redox enzymes. Recent studies demonstrated that PICOT is a prerequisite for mouse embryogenesis and participates in several independent biological systems in the adult. This paper examines advances made over the past few years in understanding the role of PICOT in various biological systems.