Abstract

We have previously reported the localization of a mitochondrial DnaJ (J-domain) member - Mdj1 - on the cell surface for the first time. J-domain chaperones belong to the Hsp40 family; its members can function alone or in cooperation with Hsp70 complexes in different intracellular organelles. In the pathogenic yeast phase (Y) of the thermal dimorphic fungus P. brasiliensis Pb18 growing at 36&bullC, Mdj1p was localized to both the mitochondria and the cell wall by confocal/electronic microscopy, FACS and immunoblotting of fungal cell fractions. These experiments were carried out using rabbit anti-recombinant PbMdj1 (anti-rPbMdj1, N-terminal). We presently used anti-rPbMdj1 to show dual intracellular/cell wall confocal localization also in fully formed yeasts from isolate Pb3, which represents a criptic phylogenetic group distinct from Pb18, and also in Histoplasma capsulatum. Pb01 (P. lutzii) showed pseudohyphal growth at 36&bullC and label was preferential at the cell surface. On the other hand, fully formed Pb18 mycelia (M) growing at 23&bullC reacted with anti-rPbMdj1 mostly at the cell wall, where label was distributed along the hyphae following a punctuated pattern. We followed the reactivity with anti-rPbMdj1 during Y/M thermal transition and this preferential localization was observed specially after 48 hours. During the first days of M/Y transition, label was mostly intracellular. In Aspergillus fumigatus, anti-rPbMdj1 antibodies concentrated at the tip of growing hyphae or lateral branching points when the fungus was cultivated at 36&bullC. When growing at 23&bullC, anti-rPbMdj1 label diluted in intensity along a larger area of the hyphal tip, following a different pattern. These results suggested a role in fungal development. Function of Mdj1 at the fungal cell wall remains speculative. Support: FAPESP, CNPq, CAPES ਀㰀⼀昀漀渀琀㸀㰀⼀瀀㸀㰀戀爀㸀㰀戀㸀䬀攀礀眀漀爀搀㨀 㰀⼀戀㸀☀渀戀猀瀀㬀䄀猀瀀攀爀最椀氀氀甀猀 昀甀洀椀最愀琀甀猀Ⰰ 挀栀愀瀀攀爀漀渀攀Ⰰ 栀礀瀀栀愀攀Ⰰ 䴀搀樀㄀瀀Ⰰ 倀愀爀愀挀漀挀挀椀搀椀漀椀搀攀猀 戀爀愀猀椀氀椀攀渀猀椀猀㰀⼀琀搀㸀㰀⼀琀爀㸀㰀⼀琀愀戀氀攀㸀㰀⼀琀爀㸀㰀⼀琀搀㸀㰀⼀琀愀戀氀攀㸀㰀⼀戀漀搀礀㸀㰀⼀栀琀洀氀㸀