Cardiolipin targets a dynamin related protein to the nuclear membrane

ABSTRACTDynamins are large cytoplasmic GTPases that are targeted to specific cellular membranes which they remodel via membrane fusion or fission. Although the mechanism of target membrane selection by dynamins has been studied, the molecular basis of conferring specificity to bind specific lipids on the target membranes is not known in any of the family members. Here, we report a mechanism of nuclear membrane recruitment of Drp6 that is involved in nuclear remodeling in Tetrahymena thermophila. Recruitment of Drp6 depends on a domain that binds to cardiolipin-rich bilayers. Consistent with this, the nuclear localization of wildtype Drp6 was inhibited by depleting cardiolipin in the cell. Cardiolipin binding was blocked with a single amino acid substitution (I553M) in the membrane-binding domain of Drp6. Importantly, the I553M substitution was sufficient to block nuclear localization without affecting other properties of Drp6. Consistent with this result, co-expression of wildtype Drp6 was sufficient to rescue the localization defect of I553M variant in Tetrahymena. Inhibition of cardiolipin synthesis or perturbation in Drp6 recruitment to nuclear membrane caused defects in the formation of new macronuclei post-conjugation. Taken together, our results elucidate a molecular basis of target membrane selection by a nuclear dynamin, and establish the importance of a defined membrane-binding domain and its target lipid in facilitating nuclear expansion.

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Cardiolipin targets a dynamin related protein to the nuclear membrane

eLife ◽

10.7554/elife.64416 ◽

2021 ◽

Vol 10 ◽

Author(s):

Usha Pallabi Kar ◽

Himani Dey ◽

Abdur Rahaman

Keyword(s):

Amino Acid ◽

Nuclear Localization ◽

Nuclear Membrane ◽

Molecular Basis ◽

Single Amino Acid ◽

Related Protein ◽

Membrane Recruitment ◽

Single Amino Acid Residue ◽

Target Membrane ◽

Nuclear Expansion

Dynamins are targeted to specific cellular membranes that they remodel via membrane fusion or fission. The molecular basis of conferring specificity to dynamins for their target membrane selection is not known. Here, we report a mechanism of nuclear membrane recruitment of Drp6, a dynamin member in Tetrahymena thermophila. Recruitment of Drp6 depends on a domain that binds to cardiolipin-rich bilayers. Consistent with this, nuclear localization of Drp6 was inhibited either by depleting cellular cardiolipin (CL) or by substituting a single amino acid residue that abolished Drp6 interactions with CL. Inhibition of CL synthesis, or perturbation in Drp6 recruitment to nuclear membrane, caused defects in the formation of new macronuclei post-conjugation. Taken together, our results elucidate a molecular basis of target membrane selection by a nuclear dynamin, and establish the importance of a defined membrane-binding domain and its target lipid in facilitating nuclear expansion.

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Identification of a nuclear localization signal in the Plasmodium falciparum CTP: phosphocholine cytidylyltransferase enzyme

Scientific Reports ◽

10.1038/s41598-020-76829-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Richard Izrael ◽

Lívia Marton ◽

Gergely N. Nagy ◽

Hajnalka L. Pálinkás ◽

Nóra Kucsma ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Cell Line ◽

Nuclear Localization ◽

Nuclear Localization Signal ◽

Membrane Binding ◽

Binding Domain ◽

Regulatory Function ◽

Phosphocholine Cytidylyltransferase ◽

Phosphatidylcholine Biosynthesis ◽

Localization Signal

AbstractThe phospholipid biosynthesis of the malaria parasite, Plasmodium falciparum is a key process for its survival and its inhibition is a validated antimalarial therapeutic approach. The second and rate-limiting step of the de novo phosphatidylcholine biosynthesis is catalysed by CTP: phosphocholine cytidylyltransferase (PfCCT), which has a key regulatory function within the pathway. Here, we investigate the functional impact of the key structural differences and their respective role in the structurally unique pseudo-heterodimer PfCCT protein in a heterologous cellular context using the thermosensitive CCT-mutant CHO-MT58 cell line. We found that a Plasmodium-specific lysine-rich insertion within the catalytic domain of PfCCT acts as a nuclear localization signal and its deletion decreases the nuclear propensity of the protein in the model cell line. We further showed that the putative membrane-binding domain also affected the nuclear localization of the protein. Moreover, activation of phosphatidylcholine biosynthesis by phospholipase C treatment induces the partial nuclear-to-cytoplasmic translocation of PfCCT. We additionally investigated the cellular function of several PfCCT truncated constructs in a CHO-MT58 based rescue assay. In absence of the endogenous CCT activity we observed that truncated constructs lacking the lysine-rich insertion, or the membrane-binding domain provided similar cell survival ratio as the full length PfCCT protein.

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Molecular Basis for Lipid Specificity of the Coagulation Factor X Membrane-Binding Domain

Biophysical Journal ◽

10.1016/j.bpj.2015.11.2291 ◽

2016 ◽

Vol 110 (3) ◽

pp. 424a

Author(s):

Melanie P. Muller ◽

Emad Tajkhorshid

Keyword(s):

Molecular Basis ◽

Membrane Binding ◽

Coagulation Factor ◽

Binding Domain ◽

Factor X ◽

Lipid Specificity

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Faculty Opinions recommendation of X-ray crystal structures of the estrogen-related receptor-gamma ligand binding domain in three functional states reveal the molecular basis of small molecule regulation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1047292.497229 ◽

2006 ◽

Author(s):

Paul Webb

Keyword(s):

Ligand Binding ◽

Crystal Structures ◽

Small Molecule ◽

Molecular Basis ◽

Binding Domain ◽

Ligand Binding Domain ◽

X Ray ◽

Functional States ◽

Estrogen Related Receptor

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A single amino acid substitution flanking the fourth calcium binding domain of alpha IIb prevents maturation of the alpha IIb beta 3 integrin complex.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)41800-x ◽

1994 ◽

Vol 269 (6) ◽

pp. 4450-4457

Author(s):

D.A. Wilcox ◽

J.L. Wautier ◽

D. Pidard ◽

P.J. Newman

Keyword(s):

Amino Acid ◽

Amino Acid Substitution ◽

Calcium Binding ◽

Binding Domain ◽

Single Amino Acid Substitution ◽

Single Amino Acid ◽

Calcium Binding Domain

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The membrane-binding domain of ankyrin contains four independently folded subdomains, each comprised of six ankyrin repeats.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)41584-0 ◽

1993 ◽

Vol 268 (30) ◽

pp. 22703-22709

Author(s):

P Michaely ◽

V Bennett

Keyword(s):

Membrane Binding ◽

Binding Domain ◽

Ankyrin Repeats

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Structure of a Membrane-binding Domain from a Non-enveloped Animal Virus

Journal of Biological Chemistry ◽

10.1074/jbc.m604689200 ◽

2006 ◽

Vol 281 (39) ◽

pp. 29278-29286 ◽

Cited By ~ 20

Author(s):

Lenize F. Maia ◽

Márcia R. Soares ◽

Ana P. Valente ◽

Fabio C. L. Almeida ◽

Andréa C. Oliveira ◽

...

Keyword(s):

Membrane Binding ◽

Binding Domain ◽

Animal Virus

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Mutation of Dileucine-Like Motifs in the Human Immunodeficiency Virus Type 1 Capsid Disrupts Virus Assembly, Gag-Gag Interactions, Gag-Membrane Binding, and Virion Maturation

Journal of Virology ◽

10.1128/jvi.00355-06 ◽

2006 ◽

Vol 80 (16) ◽

pp. 7939-7951 ◽

Cited By ~ 47

Author(s):

Anjali Joshi ◽

Kunio Nagashima ◽

Eric O. Freed

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Particle Production ◽

Virus Assembly ◽

Membrane Binding ◽

Single Amino Acid ◽

Immunodeficiency Virus ◽

Hiv 1

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) Gag precursor protein Pr55Gag drives the assembly and release of virus-like particles in the infected cell. The capsid (CA) domain of Gag plays an important role in these processes by promoting Gag-Gag interactions during assembly. The C-terminal domain (CTD) of CA contains two dileucine-like motifs (L189/L190 and I201/L202) implicated in regulating the localization of Gag to multivesicular bodies (MVBs). These dileucine-like motifs are located in the vicinity of the CTD dimer interface, a region of CA critical for Gag-Gag interactions during virus assembly and CA-CA interactions during core formation. To study the importance of the CA dileucine-like motifs in various aspects of HIV-1 replication, we introduced a series of mutations into these motifs in the context of a full-length, infectious HIV-1 molecular clone. CA mutants LL189,190AA and IL201,202AA were both severely impaired in virus particle production because of a variety of defects in the binding of Gag to membrane, Gag multimerization, and CA folding. In contrast to the model suggesting that the CA dileucine-like motifs regulate MVB targeting, the IL201,202AA mutation did not alter Gag localization to the MVB in either HeLa cells or macrophages. Revertants of single-amino-acid substitution mutants were obtained that no longer contained dileucine-like motifs but were nevertheless fully replication competent. The varied phenotypes of the mutants reported here provide novel insights into the interplay among Gag multimerization, membrane binding, virus assembly, CA dimerization, particle maturation, and virion infectivity.

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