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IP3 receptor activity is differentially regulated in endoplasmic reticulum subdomains during oocyte maturation. Curr Biol 2005 Apr 26;15(8):765-70 PMID: 15854911

Abstract

Fertilization competency results from hormone-induced remodeling of oocytes into eggs. The signaling pathways that effect this change exemplify bistability, where brief hormone exposure irrevocably switches cell fate. In Xenopus, changes in Ca(2+) signaling epitomize such remodeling: The reversible Ca(2+) signaling phenotype of oocytes rapidly adapts to support irreversible propagation of the fertilization Ca(2+) wave. Here, we simultaneously resolved IP(3) receptor (IP(3)R) activity with endoplasmic reticulum (ER) structure to optically dissect the functional architecture of the Ca(2+) release apparatus underpinning this reorganization. We show that changes in Ca(2+) signaling correlate with IP(3)R redistribution from specialized ER substructures called annulate lamellae (AL), where Ca(2+) release activity is attenuated, into IP(3)R-replete patches in the cortical ER of eggs that support the fertilization Ca(2+) wave. These data show: first, that IP(3)R sensitivity is regulated with high spatial acuity even between contiguous ER regions; and second, that drastic reorganization of Ca(2+) signaling dynamics can be driven by subcellular redistribution in the absence of changes in channel number or molecular or familial Ca(2+) channel diversity. Finally, these results define a novel role for AL in Ca(2+) signaling. Because AL are prevalent in other scenarios of rapid cell division, further studies of their impact on Ca(2+) signaling are warranted.

Author List

Boulware MJ, Marchant JS

Author

Jonathan S. Marchant PhD Chair, Professor in the Cell Biology, Neurobiology and Anatomy department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Calcium
Calcium Channels
Endoplasmic Reticulum
Female
Fertilization
Fluorescence Resonance Energy Transfer
Inositol 1,4,5-Trisphosphate Receptors
Microscopy, Confocal
Oocytes
Ovum
Receptors, Cytoplasmic and Nuclear
Signal Transduction
Xenopus laevis



View this publication's entry at the Pubmed website PMID: 15854911
jenkins-FCD Prod-130 96200611f8481f0aa4f84230b11dd74d063847a3