Membrane protein SMP-1 is required for normal flagellum function in<i>Leishmania</i>

Tull, Dedreia; Naderer, Thomas; Spurck, Timothy P.; Mertens, Haydyn D. T.; Heng, Joanne; McFadden, Geoffrey I.; Gooley, Paul R.; McConville, Malcolm J.

doi:10.1242/jcs.059097

Cited by 36 publications

(46 citation statements)

References 70 publications

(108 reference statements)

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“…One distinct feature of the S4D-overexpressing cells is that these cells are stumpy with small flagella, morphologically similar to ADF/ cofilin gene knockout mutants (52), myosin XXI heterozygous gene deletion mutants (33), and many other flagellar mutants (2,16,18,26,53,56), including a recently reported dysflagellar strain of L. braziliensis (59). Based on these studies, we envisage that like in Trypanosoma brucei (1,35), a correlation may exist between the flagellar length and the cell body length.…”

Section: Discussionmentioning

confidence: 75%

“…As the PFR assembles only on the flagellar region outside the flagellar pocket region, it may be argued that a minimum length of the axoneme is required for PFR assembly. There are two supports to this hypothesis: (i) the null mutant of SMP-1 (a flagellar membrane protein) shows a flagellar length averaging around 7 m with fully assembled PFR (53), and (ii) about 17% of the total population of one of the two null mutants of LmxMPK3 (mutant ⌬2), having an average flagellar length of about 6.7 m, show normal PFR architecture (18). However, this argument can be downplayed through two separate studies, one on the same SMP-1 protein where cells treated with myriosin and ketoconazole bore a very short axoneme (54) and the other on null mutants of the outer dynein arm-docking complex (LdDC2), having mean flagellar lengths of 3.7 m and 2.9 m (26).…”

Section: Discussionmentioning

confidence: 97%

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Overexpression of S4D Mutant of Leishmania donovani ADF/Cofilin Impairs Flagellum Assembly by Affecting Actin Dynamics

et al. 2012

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Leishmania, like other eukaryotes, contains large amounts of actin and a number of actin-related and actin binding proteins. Our earlier studies have shown that deletion of the gene corresponding to Leishmania actin-depolymerizing protein (ADF/cofilin) adversely affects flagellum assembly, intracellular trafficking, and cell division. To further analyze this, we have now created ADF/cofilin site-specific point mutants and then examined (i) the actin-depolymerizing, G-actin binding, and actin-bound nucleotide exchange activities of the mutant proteins and (ii) the effect of overexpression of these proteins in wild-type cells. Here we show that S4D mutant protein failed to depolymerize F-actin but weakly bound G-actin and inhibited the exchange of G-actin-bound nucleotide. We further observed that overexpression of this protein impaired flagellum assembly and consequently cell motility by severely impairing the assembly of the paraflagellar rod, without significantly affecting vesicular trafficking or cell growth. Taken together, these results indicate that dynamic actin is essentially required in assembly of the eukaryotic flagellum. Reorganization of actin cytoskeleton is central to several fundamental processes in eukaryotes, including cell division, cell shape regulation and, transmission of extracellular stimuli toward the cell interior. Such diverse functions of actin cytoskeleton have been attributed to the dynamic character of actin, which requires high turnover of actin monomers in its filamentous meshwork by a treadmilling process (11). This process is greatly facilitated by the actin-depolymerizing protein (ADF)/cofilin family of actin binding proteins (40). These proteins generally have three distinct biochemical activities, viz., F-actin depolymerization, actin filament severing, and nucleotide exchange (12). By virtue of these activities, ADF/cofilins play a key role in regulating the actin dynamics and associated functions in eukaryotes (7). Functions of the actin cytoskeleton have been considered important not only in higher eukaryotes but also in several parasites that cause lifethreatening human diseases, such as Plasmodium (5, 49), Acanthamoeba (10, 23), Trypanosoma (13, 21), Leishmania (30, 47), and others.Leishmania spp. constitute a group of medically important protozoan parasites that are responsible for a vast array of devastating human diseases, including kala-azar (visceral leishmaniasis). These organisms exist in two morphobiological forms, amastigotes (inside the human host) and promastigotes (in the insect vector), which undergo extensive cytoskeletal rearrangement during their transformation from one form to the other (25). The promastigote form possesses a single highly motile protruding flagellum, which drives the cell to move forward, whereas the rudimentary flagellum in amastigotes has been considered important to establish host-parasite interactions (22). Further, a direct involvement of the promastigote flagellum has been demonstrated in sandfly infection (16). Apart from being ...

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Section: Discussionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 97%

Overexpression of S4D Mutant of Leishmania donovani ADF/Cofilin Impairs Flagellum Assembly by Affecting Actin Dynamics

et al. 2012

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“…FLAG1/SMP1 was found to be a well-conserved protein present in all Leishmania investigated so far. By immunofluorescence, the anti-FLAG1/SMP1 monoclonal antibody reacted with the flagellum of L. braziliensis, L. i. chagasi, L. donovani, L. guyanensis, L. major, L. mexicana, L. panamensis, and L. pifanoi (Córdova-Rojas 1998, Tull et al 2010our results). Western blots of L. amazonensis, L. i. chagasi, L. donovani, L. major, L. mexicana, and L. pifanoi using the anti-FLAG1/SMP1 antibody produced the expected band of approximately 15 kD.…”

Section: Discussionmentioning

confidence: 99%

The Flagellar Protein FLAG1/SMP1 is a Candidate forLeishmania–Sand Fly Interaction

Di-Blasi

Lobo

Nascimento

et al. 2015

Vector-Borne and Zoonotic Diseases

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Leishmaniasis is a serious problem that affects mostly poor countries. Various species of Leishmania are the agents of the disease, which take different clinical manifestations. The parasite is transmitted by sandflies, predominantly from the Phlebotomus genus in the Old World and Lutzomyia in the New World. During development in the gut, Leishmania must survive various challenges, which include avoiding being expelled with blood remnants after digestion. It is believed that attachment to the gut epithelium is a necessary step for vector infection, and molecules from parasites and sand flies have been implicated in this attachment. In previous work, monoclonal antibodies were produced against Leishmania. Among these an antibody was obtained against Leishmania braziliensis flagella, which blocked the attachment of Leishmania panamensis flagella to Phlebotomus papatasi guts. The protein recognized by this antibody was identified and named FLAG1, and the complete FLAG1 gene sequence was obtained. This protein was later independently identified as a small, myristoylated protein and called SMP1, so from now on it will be denominated FLAG1/SMP1. The FLAG1/SMP1 gene is expressed in all developmental stages of the parasite, but has higher expression in promastigotes. The anti-FLAG1/SMP1 antibody recognized the flagellum of all Leishmania species tested and generated the expected band by western blots. This antibody was used in attachment and infection blocking experiments. Using the New World vector Lutzomyia longipalpis and Leishmania infantum chagasi, no inhibition of attachment ex vivo or infection in vivo was seen. On the other hand, when the Old World vectors P. papatasi and Leishmania major were used, a significant decrease of both attachment and infection were seen in the presence of the antibody. We propose that FLAG1/SMP1 is involved in the attachment/infection of Leishmania in the strict vector P. papatasi and not the permissive vector L. longipalpis.

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“…In addition, knockdown/knockout of acylated proteins has been used to determine the function of these proteins and their effects on virulence. Knockout of s mall m yristoylated p rotein 1 (LmSMP-1) and LmSMP-2 in L. major causes flagellar shortening and defective motility [65], which may affect the virulence of the parasite in vivo . Knockdown of myristoylated TbARL or LdARL is lethal [64].…”

Section: Acylation and Growthmentioning

confidence: 99%

Acylation in trypanosomatids: an essential process and potential drug target

Goldston

Sharma

Paul

et al. 2014

Trends in Parasitology

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Fatty acylation—the addition of fatty acid moieties such as myristate and palmitate to proteins—is essential for the survival, growth, and infectivity of the trypanosomatids: Trypanosoma brucei, Trypanosoma cruzi, and Leishmania. Myristoylation and palmitoylation are critical for parasite growth, targeting and localization, and the intrinsic function of some proteins. The trypanosomatids possess a single N-myristoyltransferase (NMT) and multiple palmitoyl acyltransferases, and these enzymes and their cellular targets are only now being characterized. Global inhibition of either process leads to cell death in trypanosomatids, and genetic ablation of NMT compromises virulence. Moreover, NMT inhibitors effectively cure T. brucei infection in rodents. Thus, protein acylation represents an attractive target for the development of trypanocidal drugs.

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Membrane protein SMP-1 is required for normal flagellum function inLeishmania

Cited by 36 publications

References 70 publications

Overexpression of S4D Mutant of Leishmania donovani ADF/Cofilin Impairs Flagellum Assembly by Affecting Actin Dynamics

Overexpression of S4D Mutant of Leishmania donovani ADF/Cofilin Impairs Flagellum Assembly by Affecting Actin Dynamics

The Flagellar Protein FLAG1/SMP1 is a Candidate forLeishmania–Sand Fly Interaction

Acylation in trypanosomatids: an essential process and potential drug target

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