Differential splicing-in of a proline-rich exon converts alphaNAC into a muscle-specific transcription factor.

Yotov, Wagner V.; St‐Arnaud, René

doi:10.1101/gad.10.14.1763

Cited by 83 publications

(105 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Interestingly, it had been recently reported that ␣NAC binds to DNA in a sequence-specific manner. A consensus sequence for binding of ␣NAC to DNA was published (5Ј-(G/C)(G/ C)A(G/C)A(G/C)ANNNG-3Ј) (25). We confirmed binding of ␣NAC to oligonucleotides containing this motif; however, we also observed binding to oligonucleotides where this motif was mutated (data not shown).…”

Section: Fig 4 Recombinant Nac Interacts With Nascent Chains On Ribsupporting

confidence: 58%

The α and β Subunit of the Nascent Polypeptide-associated Complex Have Distinct Functions

Beatrix

Sakai

Wiedmann

2000

Journal of Biological Chemistry

View full text Add to dashboard Cite

Nascent polypeptide-associated complex (NAC) is probably the first cytosolic protein to contact nascent polypeptide chains emerging from ribosomes. In this way NAC prevents inappropriate interactions with other factors. Eventually other factors involved in targeting and folding, like the Signal Recognition Particle or cytosolic chaperones, must gain access to the nascent chain. All NAC preparations to date consist of two copurifying polypeptides. Here we rigorously show that these two polypeptides, termed ␣-and ␤NAC, form a very stable complex in vivo and in vitro and that a functional complex can be reconstituted from the individual subunits. A dissection of the contributions of the individual subunits to NACs function revealed that both subunits are in direct contact with nascent polypeptide chains on the ribosome and that both contribute to the prevention of inappropriate interactions. However, ␤NAC alone directly binds to the ribosome and is sufficient to prevent ribosome binding to the endoplasmic reticulum membrane. Nascent polypeptide-associated complex (NAC) 1 is a very abundant cytosolic protein, which is involved in cotranslational targeting of polypeptides to the endoplasmic reticulum (ER) membrane. The intracellular NAC concentration varies only slightly in different tissues, ranging from 3 to 10 M (1). NAC is highly conserved among eukaryotes, but up to now no functional prokaryotic homolog has been described. The importance of NACs in vivo function is emphasized by early embryonically lethal phenotypes of NAC mutants in mice and fruit flies (2, 3). Recently it was also shown that yeast NAC, although not essential for growth (4), is involved in the import of proteins into mitochondria (5, 6).NAC was originally identified as a ribosome-associated protein when we set out to probe the molecular environment of growing polypeptides on the ribosome using a photo-cross-linking approach (7). With this technique we were able to show that NAC can interact with regions of nascent chains as close as 17 amino acids to the peptidyl transferase center. Additionally, it was shown by protease protection that NAC functions as a dissociable wall of a ribosomal tunnel through which the growing polypeptide emerges (8). Cycles of binding and releasing NAC expose the polypeptide to the cytosol in "quantal units" rather than amino acid by amino acid. We have proposed that exposing the polypeptide chain in functional units contributes to fidelity in cotranslational processes such as targeting and folding (9). Depleting NAC from translating ribosomes led to at least two inappropriate interactions. First, the signal recognition particle (SRP), which interacts with signal peptides of nascent chains on ribosomes during targeting to the ER membrane, could be cross-linked to nascent chains lacking signal peptides (7). Second, in the absence of NAC ribosomes translating non-secretory polypeptides inappropriately interacted with translocation sites on ER membranes and the signal-less chains were even translocated, although with l...

show abstract

Section: Fig 4 Recombinant Nac Interacts With Nascent Chains On Ribsupporting

confidence: 58%

The α and β Subunit of the Nascent Polypeptide-associated Complex Have Distinct Functions

Beatrix

Sakai

Wiedmann

2000

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…NACA appears to be part of the chaperon system that ensures the proper folding of nascent proteins, notably those to be translocated in the endoplasmic reticulum, ER 12,13 . The naca gene also encodes a muscle-specific, much larger isoform, skNAC, through differential RNA splicing 14,15 . NACA and skNAC have also been described as transcriptional co-activators in osteoblasts and myotubes, respectively 14,16,17 .…”

Section: Resultsmentioning

confidence: 99%

“…The naca gene also encodes a muscle-specific, much larger isoform, skNAC, through differential RNA splicing 14,15 . NACA and skNAC have also been described as transcriptional co-activators in osteoblasts and myotubes, respectively 14,16,17 .…”

Section: Resultsmentioning

confidence: 99%

NACA deficiency reveals the crucial role of somite-derived stromal cells in haematopoietic niche formation

et al. 2015

View full text Add to dashboard Cite

“…Table 1 lists proteins for which we have used strains of E. coli that over-express Hsp90 (Plus90α™; Plus90β™; Expression Technologies Inc., San Diego, CA) to prevent aggregation during expression [45][46][47][48][49][50][51][52]. This illustrates the structural and functional disparity among the in vitro clientele of Hsp90.…”

Section: Hsp90 Client Proteinsmentioning

confidence: 99%

Hsp90—From signal transduction to cell transformation

Brown

Zhu

Schmidt

et al. 2007

Biochemical and Biophysical Research Communications

View full text Add to dashboard Cite

The molecular chaperone, Hsp90, facilitates the maturation and/or activation of over 100 'client proteins' involved in signal transduction and transcriptional regulation. Largely an enigma among the families of heat shock proteins, Hsp90 is central to processes broadly ranging from cell cycle regulation to cellular transformation. Here we review the contemporary body of knowledge regarding the biochemical mechanisms of Hsp90 and update the most current paradigms defining its involvement in both normal and pathological cell physiology. KeywordsHsp90; heat shock protein; molecular chaperone; ATPase; genetic capacitor Hsp90 defines a family of molecular chaperones that are highly conserved from prokaryotes to eukaryotes [1][2][3][4][5]. Nonessential for normal growth in most bacteria, Hsp90 is abundantly expressed in higher eukaryotes where it has been shown to be necessary for viability [6,7]. It functions as a homodimer that associates with co-chaperones to catalyze the maturation and/ or activation of over 100 substrate proteins that are known to be involved in cell regulatory pathways [5]. These 'client proteins' include protein kinases, nuclear hormone receptors, transcription factors, and an array of other essential proteins [8]. While much is known regarding the ATPase-driven conformational cycling of Hsp90, the precise physical effects imparted by this chaperone that serve to activate its substrates are still poorly understood [5]. Hsp90 architectureThree highly conserved domains comprise the structure of Hsp90. These include the N-terminal domain, responsible for ATP-binding, a proteolytically resistant core domain, and the Cterminal domain that facilitates homodimerization (Fig. 1a) [9]. In eukaryotes, a more variable charged region links the N-terminal domain to the core domain. The length and composition of this linker region is highly divergent among organisms [10]. As no atomic resolution structure for full-length Hsp90 is yet available, the most thorough structural analyses for Hsp90, to date, have been based on crystallographic studies of its individual domains.A mechanistic understanding of Hsp90 was nebulous until partial sequence homology was recognized between its N-terminal domain and two types of ATP-dependent proteins. These

show abstract

Differential splicing-in of a proline-rich exon converts alphaNAC into a muscle-specific transcription factor.

Cited by 83 publications

References 46 publications

The α and β Subunit of the Nascent Polypeptide-associated Complex Have Distinct Functions

The α and β Subunit of the Nascent Polypeptide-associated Complex Have Distinct Functions

NACA deficiency reveals the crucial role of somite-derived stromal cells in haematopoietic niche formation

Hsp90—From signal transduction to cell transformation

Contact Info

Product

Resources

About