QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 18, Issue 2, 547-556, February 2007

This Article Full Text Full Text (PDF) Supplemental Material All Versions of this Article: E06-09-0776v1 18/2/547    most recent Alert me when this article is cited Alert me if a correction is posted Services 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 Aguilar, P. S. Articles by Walter, P. Search for Related Content PubMed PubMed Citation Articles by Aguilar, P. S. Articles by Walter, P.

The Plasma Membrane Proteins Prm1 and Fig1 Ascertain Fidelity of Membrane Fusion during Yeast Mating

Howard Hughes Medical Institute, and Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA 94158

Submitted September 1, 2006; Revised November 20, 2006; Accepted November 22, 2006
Monitoring Editor: Charles Boone

As for most cell–cell fusion events, the molecular details of membrane fusion during yeast mating are poorly understood. The multipass membrane protein Prm1 is the only known component that acts at the step of bilayer fusion. In its absence, mutant mating pairs lyse or arrest in the mating reaction with tightly apposed plasma membranes. We show that deletion of FIG 1, which controls pheromone-induced Ca²⁺ influx, yields similar cell fusion defects. Although extracellular Ca²⁺ is not required for efficient cell fusion of wild-type cells, cell fusion in prm1 mutant mating pairs is dramatically reduced when Ca²⁺ is removed. This enhanced fusion defect is due to lysis. Time-lapse microscopy reveals that fusion and lysis events initiate with identical kinetics, suggesting that both outcomes result from engagement of the fusion machinery. The yeast synaptotagmin orthologue and Ca²⁺ binding protein Tcb3 has a role in reducing lysis of prm1 mutants, which opens the possibility that the observed role of Ca²⁺ is to engage a wound repair mechanism. Thus, our results suggest that Prm1 and Fig1 have a role in enhancing membrane fusion and maintaining its fidelity. Their absence results in frequent mating pair lysis, which is counteracted by Ca²⁺-dependent membrane repair.

The online version of this article contains supplemental material at MBC Online (http://www.molbiolcell.org).

* These authors contributed equally to this work.

Address correspondence to: Pablo S. Aguilar (pablo.aguilar{at}ucsf.edu)

This article has been cited by other articles:

				A. Engel and P. Walter Membrane lysis during biological membrane fusion: collateral damage by misregulated fusion machines J. Cell Biol., October 20, 2008; 183(2): 181 - 186. [Abstract] [Full Text] [PDF]

				Y. Liu, R. Tewari, J. Ning, A. M. Blagborough, S. Garbom, J. Pei, N. V. Grishin, R. E. Steele, R. E. Sinden, W. J. Snell, et al. The conserved plant sterility gene HAP2 functions after attachment of fusogenic membranes in Chlamydomonas and Plasmodium gametes Genes & Dev., April 15, 2008; 22(8): 1051 - 1068. [Abstract] [Full Text] [PDF]

				V. J. Starai, Y. Jun, and W. Wickner From the Cover: Feature Article: Excess vacuolar SNAREs drive lysis and Rab bypass fusion PNAS, August 21, 2007; 104(34): 13551 - 13558. [Abstract] [Full Text] [PDF]