Translator Disclaimer
1 May 2001 The I-antigens of Ichthyophthirius multifiliis are GPI-Anchored Proteins
Author Affiliations +
Abstract

The parasitic ciliate Ichthyophthirius multifiliis has abundant surface membrane proteins (i-antigens) that when clustered, trigger rapid, premature exit from the host. Similar antigens are present in free-living ciliates and are GPI-anchored in both Paramecium and Tetrahymena. Although transmembrane signalling through GPI-anchored proteins has been well-documented in metazoan cells, comparable phenomena have yet to be described in protists. Since premature exit of Ichthyophthirius is likely to involve a transmembrane signalling event, we sought to determine whether i-antigens are GPI-anchored in these cells as well. Based on their solubility properties in Triton X-114, the i-antigens of Ichthyophthirius are amphiphilic in nature and partition with the detergent phase. Nevertheless, following treatment of detergent lysates with phospholipase C, the same proteins become hydrophilic. Concomitantly, they are recognized by antibodies against a cross-reacting determinant exposed on virtually all GPI-anchored proteins following cleavage with phospholipase C. Finally, when expressed in recombinant form in Tetrahymena thermophila, full-length i-antigens are restricted to the membrane, while those lacking hydrophobic C-termini are secreted from the cell. Taken together, these observations argue strongly that the i-antigens of Ichthyophthirius multifiliis are, in fact, GPI-anchored proteins.

THEODORE G. CLARK, YAN GAO, JACEK GAERTIG, XUTING WANG, and GEORGINA CHENG "The I-antigens of Ichthyophthirius multifiliis are GPI-Anchored Proteins," The Journal of Eukaryotic Microbiology 48(3), 332-337, (1 May 2001). https://doi.org/10.1111/j.1550-7408.2001.tb00322.x
Received: 14 August 2000; Accepted: 30 January 2001; Published: 1 May 2001
JOURNAL ARTICLE
6 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top