N-terminal palmitoylation is required for Toxoplasma gondii HSP20 inner membrane complex localization

Biochim Biophys Acta. 2013 Feb 25. pii: S0167-4889(13)00080-3. doi: 10.1016/j.bbamcr.2013.02.022. [Epub ahead of print]

N-terminal palmitoylation is required for Toxoplasma gondii HSP20 inner membrane complex localization

Napoli MG, Miguel ND, Lebrun M, Moreno SN, Angel SO, Corvi MM.

Laboratorio de Parasitología Molecular, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomus (IIB-INTECH), Universidad Nacional de San Martín (UNSAM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Intendente Marino Km 8,2 (B7130) Chascomús, Provincia de Buenos Aires, Argentina.

Toxoplasma gondii is an obligate intracellular parasite and the causative agent of toxoplasmosis. Protein palmitoylation is known to play roles in signal transduction and in enhancing the hydrophobicity of proteins thus contributing to their membrane association. Global inhibition of protein palmitoylation has been shown to affect T. gondii physiology and invasion of the host cell. However, the proteins affected by this modification have been understudied. This paper shows that the small heat shock protein 20 from T. gondii (TgHSP20) is synthesized as a mature protein in the cytosol and is palmitoylated in three cysteine residues. However, its localization at the inner membrane complex (IMC) is dependent only on N-terminal palmitoylation. Absence or incomplete N-terminal palmitoylation causes TgHSP20 to partially accumulate in a membranous structure. Interestingly, TgHSP20 palmitoylation is not responsible for its interaction with the daughter cells IMCs. Together, our data describe the importance of palmitoylation in protein targeting to the IMC in T. gondii.

 PMID: 23485398 [PubMed - as supplied by publisher]