FLN-1/filamin is required for maintenance of actin and exit of fertilized oocytes from the spermatheca in C. elegans.
Filamin, known primarily for its actin cross-linking function, is a stretch-sensitive structural and signaling scaffold that binds transmembrane receptors and a wide variety of intracellular signaling proteins. The Caenorhabditis elegans filamin ortholog, FLN-1, has a well conserved overall structure, including an N-terminal actin-binding domain, and a series of 20 immunoglobulin (Ig)-like repeats. FLN-1 partially colocalizes with actin filaments in spermathecal and uterine cells. Analysis of phenotypes resulting from a deletion allele and RNAi depletion indicates FLN-1 is required to maintain the actin cytoskeleton in the spermatheca and uterus, and to allow the exit of embryos from the spermatheca. FLN-1 deficient animals accumulate embryos in the spermatheca, lay damaged and unfertilized eggs, and consequently exhibit dramatically reduced brood sizes. The phospholipase PLC-1 is also required for the exit of embryos from the spermatheca, and analysis of doubly mutant animals suggests that PLC-1 and FLN-1 act in the same pathway to promote proper transit of embryos from the spermatheca to the uterus. Given the modular protein structure, subcellular localization, genetic interaction with PLC-1, and known mechanosensory functions of filamin, we postulate that FLN-1 may be required to convert mechanical information about the presence of the oocyte into a biochemical signal, thereby allowing timely exit of the embryo from the spermatheca.
Kovacevic
Ismar
I
Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Ave, Boston, MA 02115, USA.
Cram
Erin J
EJ
D000199:Actins / Q000378:metabolism*; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D003285:Contractile Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D005260:Female; D005298:Fertility / Q000235:genetics / Q000502:physiology; D064448:Filamins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D005835:Genitalia / Q000254:growth & development / Q000502:physiology; D008297:Male; D008840:Microfilament Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D009865:Oocytes / Q000502:physiology*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D034622:RNA Interference; D015398:Signal Transduction / Q000502:physiology
D000199:Actins; D029742:Caenorhabditis elegans Proteins; D003285:Contractile Proteins; C000604107:FLN-1 protein, C elegans; D064448:Filamins; D008840:Microfilament Proteins; D020033:Protein Isoforms