SPINK5
Developmental stage
Expressed in liver of pre-laying and egg-laying hens throughout sexual maturation. Expression increases gradually from 13 weeks of age reaching its maximum at 15 weeks of age (pre-laying hens). A significant decrease in expression is observed in 41-week-old hens (egg-laying), a level that is significantly lower than that measured initially in 13-week-old pullets.
Domain
Seems to have at least five separate non-overlapping active inhibitory domains; two for trypsin, two for chymotrypsin and one for elastase. They can be bound to the domains simultaneously.
Function
Serine protease inhibitor involved in antimicrobial egg defense preventing contamination of table eggs (non-fertilized eggs) and protecting the chick embryo (fertilized eggs) (Probable). Inhibits trypsin, chymotrypsin, elastase, subtilisin and a proteinase of fungus Aspergillus oryzae (PubMed:13944692, PubMed:14519973, PubMed:14609095, PubMed:22010862, PubMed:6838526, PubMed:6904299). Inhibits calcium-activated potassium channels KCNMA1 (bovine) and slo (Drosophila) (PubMed:8973172). Has antibacterial activity against B.thuringiensis LMSA 3.06.004, but not against S.aureus CIP 103 811, P.aeruginosa PAO1, B.cereus ATCC6464 or B.subtilis ATCC 6633 (PubMed:22010862).
Post-translational modifications
Glycosylated.
Tissue Specificity
Expressed in oviduct (at protein level) (PubMed:3571241). Expressed in egg white (at protein level) (PubMed:14519973, PubMed:23122126, PubMed:25436390, PubMed:6838526). Expressed in egg yolk plasma of non-fertilized eggs (at protein level) (PubMed:22010862). Expressed in the magnum of the oviduct (at protein level) (PubMed:25436390). Expressed in oviduct (PubMed:14609095, PubMed:3571241). Expressed in liver (PubMed:11572089, PubMed:22010862, PubMed:3571241). Expressed in the cortico-medullary border region of the bursa of Fabricius by the bursal secretory dendritic-like cells (PubMed:15252730). Highly expressed in the magnum of the oviduct, and at a lower level in uterus. Weakly expressed in white isthmus and very weakly in infundibulum. Not expressed in duodenum and kidney (PubMed:22010862).
Cellular localization
- Secreted
Alternative names
OIH, SPINK5, Ovoinhibitor, OI, OvoI, Serine protease inhibitor Kazal-type 5