Coiled Coil Domain-containing Protein 56 (CCDC56) Is a Novel Mitochondrial Protein Essential for CytochromecOxidase Function

The purpose of this work was to identify the gene defect underlying a relatively mild rod-cone dystrophy (RCD), lacking disease-causing variants in known genes implicated in inherited retinal disorders (IRD), and provide transcriptomic and immunolocalization data to highlight the best candidate. The DNA of the female patient originating from a consanguineous family revealed no large duplication or deletion, but several large homozygous regions. In one of these, a homozygous frameshift variant, c.244_246delins17 p.(Trp82Valfs*4); predicted to lead to a nonfunctional protein, was identified in CCDC51. CCDC51 encodes the mitochondrial coiled-coil domain containing 51 protein, also called MITOK. MITOK ablation causes mitochondrial dysfunction. Here we show for the first time that CCDC51/MITOK localizes in the retina and more specifically in the inner segments of the photoreceptors, well known to contain mitochondria. Mitochondrial proteins have previously been implicated in IRD, although usually in association with syndromic disease, unlike our present case. Together, our findings add another ultra-rare mutation implicated in non-syndromic IRD, whose pathogenic mechanism in the retina needs to be further elucidated.

Download Full-text

The third coiled coil domain of Atg11 is required for shaping mitophagy initiation sites

10.1101/2020.06.29.178780 ◽

2020 ◽

Author(s):

Hannah K. Margolis ◽

Sarah Katzenell ◽

Kelsie A. Leary ◽

Michael J. Ragusa

Keyword(s):

Mitochondrial Protein ◽

Coiled Coil ◽

Membrane Vesicles ◽

Scaffolding Protein ◽

Hydrophobic Residues ◽

Dimer Interface ◽

Selective Autophagy ◽

The Third ◽

Coiled Coil Domain ◽

Dimerization Interface

AbstractSelective autophagy is the capture of specific cytosolic contents in double membrane vesicles that subsequently fuse with the vacuole or lysosome, thereby delivering cargo for degradation. Selective autophagy receptors (SARs) mark the cargo for degradation and, in yeast, recruit Atg11, the scaffolding protein for selective autophagy initiation. The mitochondrial protein Atg32 is the yeast SAR that mediates mitophagy, the selective autophagic capture of mitochondria. Atg11- Atg32 interactions concentrate Atg32 into puncta that are thought to represent sites of mitophagy initiation. However, it is unclear how Atg11 concentrates Atg32 to generate mitophagy initiation sites. We show here that the coiled coil 3 (CC3) domain of Atg11 is required for concentrating Atg32 into puncta. We determined the structure of the majority of the CC3, demonstrating that the CC3 forms a parallel homodimer whose dimer interface is formed by a small number of hydrophobic residues. We further show that the CC3 dimerization interface is required for shaping Atg32 into functional mitophagy initiation sites and for delivery of mitochondria to the vacuole. Our findings suggest that Atg11 self-interactions help concentrate SARs as a necessary precondition for cargo capture.

Download Full-text

TMCC3 localizes at the three-way junctions for the proper tubular network of the endoplasmic reticulum

Biochemical Journal ◽

10.1042/bcj20190359 ◽

2019 ◽

Vol 476 (21) ◽

pp. 3241-3260

Author(s):

Sindhu Wisesa ◽

Yasunori Yamamoto ◽

Toshiaki Sakisaka

Keyword(s):

Endoplasmic Reticulum ◽

Membrane Proteins ◽

Membrane Protein ◽

Mammalian Cells ◽

Coiled Coil ◽

Transmembrane Domains ◽

Domain Family ◽

Coiled Coil Domain ◽

U2os Cells ◽

Er Membrane

The tubular network of the endoplasmic reticulum (ER) is formed by connecting ER tubules through three-way junctions. Two classes of the conserved ER membrane proteins, atlastins and lunapark, have been shown to reside at the three-way junctions so far and be involved in the generation and stabilization of the three-way junctions. In this study, we report TMCC3 (transmembrane and coiled-coil domain family 3), a member of the TEX28 family, as another ER membrane protein that resides at the three-way junctions in mammalian cells. When the TEX28 family members were transfected into U2OS cells, TMCC3 specifically localized at the three-way junctions in the peripheral ER. TMCC3 bound to atlastins through the C-terminal transmembrane domains. A TMCC3 mutant lacking the N-terminal coiled-coil domain abolished localization to the three-way junctions, suggesting that TMCC3 localized independently of binding to atlastins. TMCC3 knockdown caused a decrease in the number of three-way junctions and expansion of ER sheets, leading to a reduction of the tubular ER network in U2OS cells. The TMCC3 knockdown phenotype was partially rescued by the overexpression of atlastin-2, suggesting that TMCC3 knockdown would decrease the activity of atlastins. These results indicate that TMCC3 localizes at the three-way junctions for the proper tubular ER network.

Download Full-text

Faculty Opinions recommendation of The Rad50 coiled-coil domain is indispensable for Mre11 complex functions.

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

10.3410/f.717967809.793467391 ◽

2012 ◽

Author(s):

John Tainer

Keyword(s):

Coiled Coil ◽

Coiled Coil Domain ◽

Mre11 Complex ◽

Complex Functions

Download Full-text

The coiled-coil domain of EspA is essential for the assembly of the type III secretion translocon on the surface of enteropathogenic Escherichia coli. Vol. 274 (1999) 35969–35974

Journal of Biological Chemistry ◽

10.1016/s0021-9258(20)67595-0 ◽

2005 ◽

Vol 280 (19) ◽

pp. 19436

Author(s):

Robin M. Delahay ◽

Stuart Knutton ◽

Robert K. Shaw ◽

Elizabeth L. Hartland ◽

Mark J. Pallen ◽

...

Keyword(s):

Escherichia Coli ◽

Type Iii Secretion ◽

Coiled Coil ◽

Enteropathogenic Escherichia Coli ◽

Type Iii ◽

Coiled Coil Domain

Download Full-text

The git5 Gβ and git11 Gγ Form an Atypical Gβγ Dimer Acting in the Fission Yeast Glucose/cAMP Pathway

Genetics ◽

10.1093/genetics/157.3.1159 ◽

2001 ◽

Vol 157 (3) ◽

pp. 1159-1168 ◽

Cited By ~ 5

Author(s):

Sheila Landry ◽

Charles S Hoffman

Keyword(s):

Fission Yeast ◽

Mammalian Cells ◽

Glucose Repression ◽

Coiled Coil ◽

Carboxy Terminus ◽

Amino Terminal ◽

Camp Pathway ◽

Coiled Coil Domain ◽

Mutational Activation ◽

Two Hybrid

AbstractFission yeast adenylate cyclase, like mammalian adenylate cyclases, is regulated by a heterotrimeric G protein. The gpa2 Gα and git5 Gβ are both required for glucose-triggered cAMP signaling. The git5 Gβ is a unique member of the Gβ family in that it lacks an amino-terminal coiled-coil domain shown to be essential for mammalian Gβ folding and interaction with Gγ subunits. Using a git5 bait in a two-hybrid screen, we identified the git11 Gγ gene. Co-immunoprecipitation studies confirm the composition of this Gβγ dimer. Cells deleted for git11 are defective in glucose repression of both fbp1 transcription and sexual development, resembling cells lacking either the gpa2 Gα or the git5 Gβ. Overexpression of the gpa2 Gα partially suppresses loss of either the git5 Gβ or the git11 Gγ, while mutational activation of the Gα fully suppresses loss of either Gβ or Gγ. Deletion of gpa2 (Gα), git5 (Gβ), or git11 (Gγ) confer quantitatively distinct effects on fbp1 repression, indicating that the gpa2 Gα subunit remains partially active in the absence of the Gβγ dimer and that the git5 Gβ subunit remains partially active in the absence of the git11 Gγ subunit. The addition of the CAAX box from the git11 Gγ to the carboxy-terminus of the git5 Gβ partially suppresses the loss of the Gγ. Thus the Gγ in this system is presumably required for localization of the Gβγ dimer but not for folding of the Gβ subunit. In mammalian cells, the essential roles of the Gβ amino-terminal coiled-coil domains and Gγ partners in Gβ folding may therefore reflect a mechanism used by cells that express multiple forms of both Gβ and Gγ subunits to regulate the composition and activity of its G proteins.

Download Full-text