HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by LIM, D. Articles by SANTELLA, L. Search for Related Content PubMed PubMed Citation Articles by LIM, D. Articles by SANTELLA, L.

Activation of oocytes by latrunculin A

Laboratory of Cell Biology, Stazione Zoologica ‘A. Dohrn’ Villa Comunale I-80121, Naples, Italy; and
^* Kladower Damn 25b, 14089 Berlin, Germany

¹Correspondence: Laboratory of Cell Biology, Stazione Zoologica ‘A. Dohrn’, Villa Comunale I-80121, Naples, Italy. E-mail: santella{at}alpha.szn.it

Actin depolymerization by latrunculin A (LAT-A) in mature starfish oocytes induces a massive calcium mobilization that results in the discharge of the cortical granules and in the elevation of the fertilization envelope. The Ca²⁺ liberation starts as a circumscribed subplasma membrane hotspot, which is followed by a flash of Ca²⁺ increase restricted to the cortical layer. Ca²⁺ propagates rapidly from these peripheral regions to the center of the oocyte, initiating calcium oscillations. Blockade of the inositol 1,4,5-trisphosphate receptors with heparin does not affect the liberation of Ca²⁺ at the initial hotspot or the cortical flash, but abolishes the centripetal spreading of the wave and the Ca²⁺ oscillations. In Ca²⁺-free medium, LAT-A also initiates Ca²⁺ release at a discrete cortical point, but then propagates throughout the cell without first forming the uniform cortical flash. The latter is thus linked to the influx of external Ca²⁺, somehow promoted by the depolymerization of cortical (microvillar) actin. The Ca²⁺ response to spermatozoa (i.e., peripheral hotspot, cortical flash, globalization of the signal) closely mimics that promoted by LAT-A. Thus, the initial cortical release of Ca²⁺ promoted by the sperm may be due to the depolymerization of actin.—Lim, D., Lange, K., Santella, L. Activation of oocytes by latrunculin A.

Key Words: intracellular calcium • fertilization • actin depolymerization • starfish oocytes

This article has been cited by other articles:

				Q.-Y. Sun and H. Schatten Regulation of dynamic events by microfilaments during oocyte maturation and fertilization Reproduction, February 1, 2006; 131(2): 193 - 205. [Abstract] [Full Text] [PDF]

				M. Whitaker Calcium at Fertilization and in Early Development Physiol Rev, January 1, 2006; 86(1): 25 - 88. [Abstract] [Full Text] [PDF]

				D. Lim, E. Ercolano, K. Kyozuka, G. A. Nusco, F. Moccia, K. Lange, and L. Santella The M-phase-promoting Factor Modulates the Sensitivity of the Ca2+ Stores to Inositol 1,4,5-Trisphosphate via the Actin Cytoskeleton J. Biol. Chem., October 24, 2003; 278(43): 42505 - 42514. [Abstract] [Full Text] [PDF]