title: Filamin and phospholipase C-ε are required for calcium signaling in the Caenorhabditis elegans spermatheca.
abstract: The Caenorhabditis elegans spermatheca is a myoepithelial tube that stores sperm and undergoes cycles of stretching and constriction as oocytes enter, are fertilized, and exit into the uterus. FLN-1/filamin, a stretch-sensitive structural and signaling scaffold, and PLC-1/phospholipase C-ε, an enzyme that generates the second messenger IP3, are required for embryos to exit normally after fertilization. Using GCaMP, a genetically encoded calcium indicator, we show that entry of an oocyte into the spermatheca initiates a distinctive series of IP3-dependent calcium oscillations that propagate across the tissue via gap junctions and lead to constriction of the spermatheca. PLC-1 is required for the calcium release mechanism triggered by oocyte entry, and FLN-1 is required for timely initiation of the calcium oscillations. INX-12, a gap junction subunit, coordinates propagation of the calcium transients across the spermatheca. Gain-of-function mutations in ITR-1/IP3R, an IP3-dependent calcium channel, and loss-of-function mutations in LFE-2, a negative regulator of IP3 signaling, increase calcium release and suppress the exit defect in filamin-deficient animals. We further demonstrate that a regulatory cassette consisting of MEL-11/myosin phosphatase and NMY-1/non-muscle myosin is required for coordinated contraction of the spermatheca. In summary, this study answers long-standing questions concerning calcium signaling dynamics in the C. elegans spermatheca and suggests FLN-1 is needed in response to oocyte entry to trigger calcium release and coordinated contraction of the spermathecal tissue.
authors.affiliation: Biology Department, Northeastern University, Boston, Massachusetts, United States of America.
authors.forename: Ismar
authors.initials: I
authors.lastname: Kovacevic
authors.forename: Jose M
authors.initials: JM
authors.lastname: Orozco
authors.forename: Erin J
authors.initials: EJ
authors.lastname: Cram
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000235:genetics* / Q000502:physiology; D003285:Contractile Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D064448:Filamins; D015544:Inositol 1,4,5-Trisphosphate / Q000235:genetics / Q000378:metabolism; D008297:Male; D008840:Microfilament Proteins / Q000235:genetics* / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism / Q000502:physiology; D054801:Phosphoinositide Phospholipase C / Q000235:genetics* / Q000378:metabolism; D013094:Spermatozoa / Q000378:metabolism / Q000502:physiology
chemical_list: D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D015544:Inositol 1,4,5-Trisphosphate; D054801:Phosphoinositide Phospholipase C; C423320:phospholipase C epsilon; D002118:Calcium