Journal article
The scaffolding protein RACK1 functions in IP3–dependent cellular processes in the nematode C. elegans
The FASEB journal, Vol.20(5), pp.A1287-A1287
03/2006
DOI: 10.1096/fasebj.20.5.A1287-a
Abstract
RACK1 is a scaffold protein that orchestrates numerous protein‐protein interactions and cellular signaling mechanisms. The C. elegans genome encodes a single RACK1 homolog that is >70% identical to mammalian RACK1. GFP reporters demonstrated that RACK1 is expressed in numerous worm tissues including the gonad, spermatheca, intestine and excretory cell. Systemic knockdown of RACK1 expression by RNAi feeding caused complete sterility. We carried out video microscopy in living worms to identify the cellular basis of the fertility defect. Oocytes form in the proximal gonad, a tube‐like structure that is comprised of contractile myoepithelial sheath cells and attached to the spermatheca. A signal from sperm stored in the spermatheca induces meiotic maturation in the most proximal oocyte. Secretion of an EGF‐like protein from the maturing oocyte triggers sheath cell contraction, dilation of the gonad‐spermatheca valve and ovulation. Gonads of RACK1 RNAi worms contained endomitotic oocytes, suggesting the presence of an ovulation defect. Video analysis indicated that sheath cell contraction was largely normal. However, dilation of the spermatheca valve failed to occur or occurred inappropriately after ovulation was complete, causing oocytes to reenter the gonad. Spermatheca valve function is controlled by PLC‐ε and PLC‐γ/IP3–dependent Ca2+ signaling processes. Our results suggest that RACK1 plays an essential role in PLC and/or IP3 signaling pathways. The readily observable fertility and spermatheca defects caused by RACK1 loss of function provide the basis for ongoing genetic analysis of RACK1 signaling mechanisms.
Details
- Title: Subtitle
- The scaffolding protein RACK1 functions in IP3–dependent cellular processes in the nematode C. elegans
- Creators
- Maria Victoria Espelt - Vanderbilt UniversitySonghai Chen - Vanderbilt UniversityKeith Patrick Choe - Vanderbilt UniversityJuan Xing - Vanderbilt UniversityHeidi Hamm - Vanderbilt UniversityKevin Strange - Vanderbilt University
- Resource Type
- Journal article
- Publication Details
- The FASEB journal, Vol.20(5), pp.A1287-A1287
- Publisher
- Federation of American Societies for Experimental Biology
- DOI
- 10.1096/fasebj.20.5.A1287-a
- ISSN
- 0892-6638
- eISSN
- 1530-6860
- Number of pages
- 1
- Language
- English
- Date published
- 03/2006
- Academic Unit
- Iowa Neuroscience Institute; Neuroscience and Pharmacology; Internal Medicine
- Record Identifier
- 9984071719702771
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