The amphipathic alpha helices of the toxoplasma protein GRA2 mediate post-secretory membrane association.

نویسندگان

  • C Mercier
  • M F Cesbron-Delauw
  • L D Sibley
چکیده

The Toxoplasma gondii protein GRA2 is secreted into the parasite-containing vacuole where it is rapidly and specifically targeted to a network of membranous tubules that connect with the vacuolar membrane. To examine the molecular basis of this association, we expressed an HA9 epitope-tagged form of GRA2 by stable transformation of Toxoplasma. GRA2-HA9 was correctly packaged inside the dense granules, secreted into the PV and targeted to the network, as shown by immunoelectron microscopy, immunofluorescence and cell fractionation. Expression of deletion mutants of GRA2-HA9 lacking either of two amphipathic alpha helices resulted in the production and secretion of soluble proteins which were unable to stably associate with the network. A mutant in which the amino acids of the first alpha helix were rearranged to a non-amphipathic pattern localized correctly to the network but failed to remained stably associated with the membrane. Collectively, these results demonstrate that targeting and membrane association occur by separate mechanisms and that the combination of both alpha helices is essential for stable localization of GRA2 to the network.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Construction, Expression and Preliminary Immunological Evaluation of a DNA Plasmid Encoding the GRA2 Protein of Toxoplasma gondii

Toxoplasmosis is a worldwide infection which is commonly asymptomatic but can cause serious medical problems in immunocompromised individuals and fetus. The infection also causes considerable economic loss because of abortion in livestock, mostly in sheep and goats. DNA vaccination may be a powerful approach against intracellular parasites such as Toxoplasma gondii. The goal of this study was t...

متن کامل

Conserved determinants for membrane association of nonstructural protein 5A from hepatitis C virus and related viruses.

Nonstructural protein 5A (NS5A) is a membrane-associated essential component of the hepatitis C virus (HCV) replication complex. An N-terminal amphipathic alpha helix mediates in-plane membrane association of HCV NS5A and at the same time is likely involved in specific protein-protein interactions required for the assembly of a functional replication complex. The aim of this study was to identi...

متن کامل

In Silico and in Vitroinvestigations on cry4aand cry11atoxins of Bacillus thuringiensis var Israelensis

In the present study we attempted to correlate the structure and function of the cry11a (72 kDa) and cry4a (135 kDa) proteins of Bacillus thuringiensis var israelensis. Homology modeling and secondary structure predictions were done to locate most probable regions for finding helices or strands in these proteins. The JPRED (JPRED consensus secondary structure prediction server) secondary struct...

متن کامل

High Expression of Water-Soluble Recombinant Antigenic Domains of Toxoplasma gondii Secretory Organelles

Recombinant antigenic proteins of Toxoplasma gondii are alternative source of antigens which are easily obtainable for serodiagnosis of toxoplasmosis. In this study, highly antigenic secretory organellar proteins, dense granular GRA2 and GRA3, rhoptrial ROP2, and micronemal MIC2, were analyzed by bioinformatics approach to express as water-soluble forms of antigenic domains. The transmembrane r...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Journal of cell science

دوره 111 ( Pt 15)  شماره 

صفحات  -

تاریخ انتشار 1998