Predicted to enable serine-type endopeptidase inhibitor activity. Involved in spermatid development. Located in extracellular space and secretory vesicle. Is expressed in body wall musculature; coelomocyte; reproductive tract; and in male.
WB Description
swm-1 encodes a putative secreted TIL-domain protease inhibitor that, inmales, inhibits unpolarized round spermatids from remodelling themselvesinto motile spermatozoa until their transfer to a hermaphrodite; SWM-1is also required for efficient sperm transfer, and thus for malefertility; SWM-1 is biologically active from spermatogenesis in L4larvae onward into adulthood, and functions non-autonomously, probablybeing expressed in germline; SWM-1-inhibited spermatid activationrequires SPE-8, SPE-12, and SPE-27; SWM-1 is active in hermaphroditesbut is not strongly required for fertility; SWM-1 is paralogous toC25E10.8, ISL-1, and the products of 11 other C. elegans genes; SWM-1and its relatives are collectively similar to other TIL-domain proteaseinhibitors from nematodes, insects, and vertebrates, including theDrosophila melanogaster seminal fluid protein Acp62F; SWM-1 contains twotandem TIL domains, missense mutations of which partially complement oneanother in vivo, and which therefore may inhibit two differentproteases; mutant swm-1 males can trans-activate hermaphroditespermatids by mating, but prematurely remodel their own spermatids,which then generally fail to be transferred to hermaphrodites;sporadically or artificially transferred swm-1 mutant sperm do, however,fertilize hermaphrodite eggs normally.