UFM1 Specific Peptidase 1 (UFSP1)

Like ubiquitin , ubiquitin-fold modifier-1 (UFM1) must be processed by a protease before it can conjugate with its target proteins. In mouse, the thiol protease Ufsp1 specifically processes the C terminus of Ufm1. The bound proteins were characterized by tandem mass spectrometry to obtain sufficient sequence to perform database searches. Ufsp1 encodes a deduced 217-amino acid protein with a molecular mass of 23 kD. Northern blot analysis detected Ufsp1 transcripts in all tissues tested, with significantly higher expression in brain, heart, kidney, and skeletal tissues. Two Ufsp1 transcripts were detected in most of the tissues.Ufsp1 showed much higher activity than Ufsp2, suggesting that the maturation of the Ufm1 precursor is catalyzed mainly by Ufsp1 in cells. Neither protein cleaved to ubiquitin or to other ubiquitin-like proteins.