The <i>Tetrahymena</i> chaperonin subunit CCTη gene is coexpressed with CCTγ gene during cilia biogenesis and cell sexual reproduction

Cyrne, Luísa; Guerreiro, Paulo; Cardoso, Ana Cristina; Rodrigues-Pousada, Claudina; Soares, Helena

doi:10.1016/0014-5793(96)00240-2

Cited by 456 publications

(34 citation statements)

References 42 publications

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“…Also, it was noted earlier that cytoplasmic TCP-1-related homologs were coexpressed with tubulin during the regeneration of Tetrahymena cilia [Soares et al, 1994;Cyrne et al, 1996]. The relevance of these observations to the present study stems from the facts that the TCP-1 complex is involved in folding newly-synthesized tubulin [Yaffe et al, 1992] and both HSP70 and HSP90 were identified as microtubuleassociated proteins (MAPs) before they were characterized as chaperones [see Liang and MacRae, 1997].…”

Section: Introductionsupporting

confidence: 54%

Molecular chaperones in cilia and flagella: Implications for protein turnover

Stephens

Lemieux

1999

Cell Motil. Cytoskeleton

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Section: Introductionsupporting

confidence: 54%

Molecular chaperones in cilia and flagella: Implications for protein turnover

Stephens

Lemieux

1999

Cell Motil. Cytoskeleton

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“…In neuronal tissue, PACRG is found in neurodegenerative inclusions, where it is thought to form part of a complex that includes members of the chaperonin and heat shock protein (HSP) families including HSP70, HSP90 and various TCP1 members (Imai et al, 2003). It remains to be seen if PACRG has similar binding partners in the axoneme, but it is worth noting that cilia and flagella are known to contain an HSP70 family member (Bloch and Johnson, 1995;Stephens, 1997;Stephens and Lemieux, 1999;Williams and Nelsen, 1997), an HSP90 family member (Stephens and Lemieux, 1999;Williams and Nelsen, 1997) and a chaperonin of the TCP1 family (Cyrne et al, 1996;Soares et al, 1994;Stephens and Lemieux, 1999). In addition, an HSP40 family member has recently been identified as a component of the radial spoke complex (Satouh et al, 2005;Yang et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

The Parkin co-regulated gene product, PACRG, is an evolutionarily conserved axonemal protein that functions in outer-doublet microtubule morphogenesis

Dawe

Farr

Portman

et al. 2005

Journal of Cell Science

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Eukaryotic cilia and flagella are highly conserved structures composed of a canonical 9+2 microtubule axoneme. Comparative genomics of flagellated and non-flagellated eukaryotes provides one way to identify new putative flagellar proteins. We identified the Parkin co-regulated gene, or PACRG, from such a screen. Male mice deficient in PACRG are sterile, but its function has been little explored. The flagellated protozoan parasite Trypanosoma brucei possesses two homologues of PACRG. We performed RNA interference knockdown experiments of the two genes independently and both together. Simultaneous ablation of both proteins produced slow growth and paralysis of the flagellum with consequent effects on organelle segregation. Moreover, using transmission electron microscopy, structural defects were seen in the axoneme, with microtubule doublets missing from the canonical 9+2 formation. The occurrence of missing doublets increased toward the distal end of the flagellum and sequential loss of doublets was observed along individual axonemes. GFP fusion proteins of both PACRG homologues localised along the full length of the axoneme. Our results provide the first evidence for PACRG function within the axoneme, where we suggest that PACRG acts to maintain functional stability of the axonemal outer doublets of both motile and sensory cilia and flagella.

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“…When tubulin is rapidly synthesized and assembled, CCT expression is up-regulated even after growth arrest (e.g. during spermatogenesis (54) and neurite development (31) of mammals, and cilia generation of Tetrahymena (55,56)). Apart from such cases, the primary cause for promoting CCT expression seems to be continuous cell growth.…”

Section: Growth-and Cell Cycle-dependent Expression Of Cct-wementioning

confidence: 99%

Cytosolic Chaperonin Is Up-regulated during Cell Growth

Yokota

Yanagi

Yura

et al. 1999

Journal of Biological Chemistry

112

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The chaperonin containing t-complex polypeptide 1 (CCT) is a heterooligomeric molecular chaperone assisting in the folding of actin, tubulin, and other cytosolic proteins. The expression levels of CCT subunits varied among seven mouse cell lines tested but showed a close correlation with growth rate. Both the CCT protein and mRNA levels in the human promyelolytic cell HL60 decreased concomitant with growth arrest during differentiation. More rapid decrease in CCT level occurred when the mouse interleukin (IL)-3-dependent myeloid DA3 cells were starved for IL-3. Readdition of IL-3 caused rapid resumption of CCT synthesis during synchronous growth: the maximum CCT protein and mRNA levels were observed at G 1 /S transition through early S phase. The turnover rate of CCT was nearly constant regardless of growth. Gel filtration and immunoprecipitation analyses indicated that CCT in vivo is associated with tubulin at early S phase, but not at G 0 /G 1 phase. These results demonstrated that CCT expression is strongly up-regulated during cell growth especially from G 1 /S transition to early S phase and is primarily controlled at the mRNA level. CCT appears to play important roles for cell growth by assisting in the folding of tubulin and other proteins.

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The Tetrahymena chaperonin subunit CCTη gene is coexpressed with CCTγ gene during cilia biogenesis and cell sexual reproduction

Cited by 456 publications

References 42 publications

Molecular chaperones in cilia and flagella: Implications for protein turnover

Molecular chaperones in cilia and flagella: Implications for protein turnover

The Parkin co-regulated gene product, PACRG, is an evolutionarily conserved axonemal protein that functions in outer-doublet microtubule morphogenesis

Cytosolic Chaperonin Is Up-regulated during Cell Growth

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