Title : Human
tryptase epsilon (
PRSS22 ), a new member of the chromosome 16p13.3 family of human
serine proteases expressed in airway epithelial cells
Abstract :
- Probing of the GenBank expressed sequence tag (EST) data base with varied human tryptase cDNAs identified two truncated ESTs that subsequently were found to encode overlapping portions of a novel human serine protease (designated tryptase epsilon or protease , serine S1 family member 22 (PRSS22 ))
- The tryptase epsilon gene resides on chromosome 16p13.3 within a 2.5-Mb complex of serine protease genes
- Although at least 7 of the 14 genes in this complex encode enzymatically active proteases, only one tryptase epsilon-like gene was identified
- The trachea and esophagus were found to contain the highest steady-state levels of the tryptase epsilon transcript in adult humans
- Although the tryptase epsilon transcript was scarce in adult human lung, it was present in abundance in fetal lung
- Thus, the tryptase epsilon gene is expressed in the airways in a developmentally regulated manner that is different from that of other human tryptase genes
- At the cellular level, tryptase epsilon is a major product of normal pulmonary epithelial cells, as well as varied transformed epithelial cell lines
- Enzymatically active tryptase epsilon is also constitutively secreted from these cells
- The amino acid sequence of human tryptase epsilon is 38-44% identical to those of human tryptase alpha, tryptase beta I , tryptase beta II , tryptase beta III, transmembrane tryptase / tryptase gamma , marapsin , and Esp-1 / testisin
- Nevertheless, comparative protein structure modeling and functional studies using recombinant material revealed that tryptase epsilon has a substrate preference distinct from that of its other family members
- These data indicate that the products of the chromosome 16p13.3 complex of tryptase genes evolved to carry out varied functions in humans