Purification and characterization of a microsporidian polar tube protein

Keohane, Elaine M.; Orr, George A.; Takvorian, Peter M.; Cali, Ann; Tanowitz, Herbert B.; Wittner, Murray; Weiss, Louis M.

doi:10.1016/0166-6851(96)02666-7

Cited by 31 publications

(59 citation statements)

References 10 publications

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“…It has also been observed that the portion of the tube already everted remains unchanged while the tube elongates and even changes direction at the tip (Weidner, 1982;Frixione et al, 1992). It should be noted that spores can be broken by mechanical pressure or by glass bead disruption, thus releasing polar tubes from the sides of the spores (Kudo, 1921;Keohane et al, 1994Keohane et al, , 1996a. It has been reported that polar tubes had a similar ultrastructural appearance regardless of whether they were triggered to activate and evert from the apical pole, or if they passively burst through the lateral walls of the spores (Weidner, 1982).…”

Section: Structure Of the Microsporidian Spore And Polar Tubementioning

confidence: 99%

“…Techniques have been described that permit the purification of spore coat proteins as well as polar tube proteins (Keohane et al, 1994(Keohane et al, , 1996a(Keohane et al, , 1999. With the publication of the genome of E. cuniculi this has permitted investigators to initial proteomic studies of the composition of this structure (Texier et al, 2003;Weiss L.M., unpublished data).…”

Section: The Microsporidian Spore Wallmentioning

confidence: 99%

“…Polar tubes have been observed to be rapidly digested after extrusion in digestive fluid or in the midgut of insects (Ohshima, 1937;Undeen and Epsky, 1990). The polar tube resists dissociation in 1-3% sodium dodecyl sulfate (SDS), 5-8 N H 2 SO 4 , 1-2 N HCl, chloroform, 1% guanidine HCl, 0.1 M proteinase K and 8-10 M Urea, but is soluble in 50% 2-mercaptoethanol (2-ME) or 1% dithiothreitol (DTT) (Weidner, 1972(Weidner, , 1976Keohane et al, 1994Keohane et al, , 1996aKeohane et al, , 1998aKeohane et al, , 1999. The polar tube inside the spore has been found to react in the same manner to reducing agents and detergents as everted polar tubes (Weidner, 1976(Weidner, , 1982.…”

Section: Composition Of the Microsporidian Polar Tubementioning

confidence: 99%

“…The solubility properties of polar tube proteins have facilitated their separation from other proteins in the spore permitting the development of a method for the purification of the major polar tube protein (PTP1) from microsporidian spores (Keohane et al, 1994(Keohane et al, , 1996a(Keohane et al, , 1999. Soluble polar tube preparations of G. americanus, E. hellem, E. cuniculi, E. intestinalis and B. algerae were prepared by sequentially extracting glass bead disrupted spores with 1% SDS and 9 M urea, followed by solubilisation of the residual polar tubes in 2% DTT (Keohane et al, 1994(Keohane et al, , 1996a(Keohane et al, , 1999.…”

Section: Composition Of the Microsporidian Polar Tubementioning

confidence: 99%

“…Soluble polar tube preparations of G. americanus, E. hellem, E. cuniculi, E. intestinalis and B. algerae were prepared by sequentially extracting glass bead disrupted spores with 1% SDS and 9 M urea, followed by solubilisation of the residual polar tubes in 2% DTT (Keohane et al, 1994(Keohane et al, , 1996a(Keohane et al, , 1999. PTP1 in the DTT-solubilised material was then purified to homogeneity using reverse phase high performance liquid chromatography (HPLC) (Keohane et al, 1994(Keohane et al, , 1996a(Keohane et al, , 1999. By SDS-PAGE and silver staining this purified fraction migrated at 43 kDa for G. americanus, 45 kDa for E. cuniculi and E. intestinalis, 55 kDa for E. hellem (Keohane et al, 1994(Keohane et al, , 1996a(Keohane et al, , 1999.…”

Section: Composition Of the Microsporidian Polar Tubementioning

confidence: 99%

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The microsporidian polar tube: A highly specialised invasion organelle

Weiss

2005

International Journal for Parasitology

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126

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All of the members of the Microsporidia possess a unique, highly specialised structure, the polar tube. This article reviews the available data on the organisation, structure and function of this invasion organelle. It was over 100 years ago that Thelohan accurately described the microsporidian polar tube and the triggering of its discharge. In the spore, the polar tube is connected at the anterior end, and then coils around the sporoplasm. Upon appropriate environmental stimulation the polar tube rapidly discharges out of the spore pierces a cell membrane and serves as a conduit for sporoplasm passage into the new host cell. The mechanism of germination of spores, however, remains to be definitively determined. In addition, further studies on the characterisation of the early events in the rupture of the anterior attachment complex, eversion of the polar tube as well as the mechanism of host cell attachment and penetration are needed in order to clarify the function and assembly of this structure. The application of immunological and molecular techniques has resulted in the identification of three polar tube proteins referred to as PTP1, PTP2 and PTP3. The interactions of these identified proteins in the formation and function of the polar tube remain to be determined. Data suggest that PTP1 is an O-mannosylated glycoprotein, a post-translational modification that may be important for its function. With the availability of the Encephalitozoon cuniculi genome it is now possible to apply proteomic techniques to the characterisation of the components of the microsporidian spore and invasion organelle.

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