Chaperones and multitasking proteins in the nucleolus: networking together for survival?

Bański, Piotr; Kodiha, Mohamed; Stochaj, Ursula

doi:10.1016/j.tibs.2010.02.010

Cited by 35 publications

(37 citation statements)

References 61 publications

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“…18,72 Moreover, proteomic studies have uncovered a whole network comprising various nucleolar proteins involved in stress responses. 18,[89][90][91] Altogether, these findings suggest that the mammalian cell nucleolus can operate as a stress sensor and major hub for coordinating stress responses. 18,20 Given that CBs are physically and functionally associated with the nucleolus, it is seems conceivable that CBs in concert with the nucleolus, may play a role in stress sensing and signaling pathways (reviewed in 18 ).…”

Section: Abiotic Stressmentioning

confidence: 88%

Cajal bodies and their role in plant stress and disease responses

et al. 2016

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Cajal bodies (CBs) are distinct sub-nuclear structures that are present in eukaryotic living cells and are often associated with the nucleolus. CBs play important roles in RNA metabolism and formation of RNPs involved in transcription, splicing, ribosome biogenesis, and telomere maintenance. Besides these primary roles, CBs appear to be involved in additional functions that may not be directly related to RNA metabolism and RNP biogenesis. In this review, we assess possible roles of plant CBs in RNA regulatory pathways such as nonsense-mediated mRNA decay and RNA silencing. We also summarize recent progress and discuss new non-canonical functions of plant CBs in responses to stress and disease. It is hypothesized that CBs can regulate these responses via their interaction with poly(ADP ribose)polymerase (PARP), which is known to play an important role in various physiological processes including responses to biotic and abiotic stresses. It is suggested that CBs and their components modify PARP activities and functions.

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Section: Abiotic Stressmentioning

confidence: 88%

Cajal bodies and their role in plant stress and disease responses

et al. 2016

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“…Key stress-related proteins like Hsc70/Hsp70 immediately translocate to the nucleolus during heat stress or acidosis (Audas et al, 2012;Banski et al, 2010;Welch and Feramisco, 1984).…”

Section: V454 Role Of the Nucleolus In Stress Responsementioning

confidence: 99%

Firefly luciferase mutants as sensors of proteome stress

et al. 2011

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“…Importantly, the composition of nucleoli is dynamic and modulated by changes in cell physiology (25,26). With respect to heat shock proteins, nucleoli are of particular interest, because they possibly harbor a specialized network composed of chaperones and multitasking proteins that cooperate to support cell survival under normal and stress conditions (27).In response to stress or other stimuli, cells activate kinase signaling cascades to initiate appropriate physiological reactions. Depending on the type of stress, different non-overlapping pathways are activated, although cross-talk between these routes exists.…”

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confidence: 99%

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Nucleolar Targeting of the Chaperone Hsc70 Is Regulated by Stress, Cell Signaling, and a Composite Targeting Signal Which Is Controlled by Autoinhibition

Bański

Mahboubi

Kodiha

et al. 2010

Journal of Biological Chemistry

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Hsc70s are constitutively synthesized members of the 70-kDa chaperone family; they are essential for viability and conserved among all organisms. When eukaryotic cells recover from stress, hsc70s accumulate in nucleoli by an unknown mechanism. Our studies were undertaken to characterize the signaling events and the targeting sequence required to concentrate hsc70 in the nucleoli of human cells. Here, we show that pharmacological inhibitors of phosphatidylinositol (PI) 3-kinase and MEK kinases as well as protein-tyrosine phosphatases abolished the stress-dependent nucleolar accumulation of hsc70. Furthermore, to identify the hsc70 nucleolar targeting sequence, green fluorescent protein-tagged fusion proteins with defined segments of hsc70 were generated and their subcellular distribution was analyzed in growing cells. These studies demonstrated that residues 225 to 297 serve as a heat-inducible nucleolar targeting signal. This segment directs green fluorescent protein to nucleoli in response to stress, but fails to do so under nonstress conditions. Fine mapping of the nucleolar targeting signal revealed that it has two separable functions. First, residues 225 to 262 direct reporter proteins constitutively to nucleoli, even without stress. Second, segment 263 to 287 functions as an autoinhibitory element that prevents hsc70 from concentrating in nucleoli when cells are not stressed. Taken together, PI 3-kinase and MEK kinase signaling as well as tyrosine dephosphorylation are essential for the accumulation of hsc70 in nucleoli of stressed cells. This process relies on a stress-dependent composite targeting signal that combines multiple functions.Heat shock cognate proteins 70 (hsc70) 4 are members of the 70-kDa family of chaperones, which are conserved among all organisms. Unlike cytoplasmic hsp70s, hsc70s are constitutively synthesized and essential for cell survival (1). Hsp/hsc70s are involved in a large number of cellular processes: they contribute to the proper folding of nascent polypeptides, refolding of denatured proteins, and targeting of damaged proteins to the proteasome (reviewed in Refs. 2-4). Hsp/hsc70s are essential for protein sorting to organelles and play a protective role in many human diseases and pathophysiologies, including Alzheimer and Huntington disease or ischemia of the heart and brain (reviewed in Refs. 5 and 6). Furthermore, defects in chaperone function have been linked to human disease and aging (5, 7-9).Members of the hsp/hsc70 family are organized into three domains; the 44-kDa N-terminal ATPase domain is followed by a protein binding segment of 18 kDa and a 10-kDa variable domain at the C-terminal end (reviewed in Ref. 3). Under normal growth conditions, hsc70s shuttle between the nucleus and the cytoplasm; however, hsc70s shuttling is inhibited upon stress (10). Following heat shock, hsc70s initially accumulate in the nucleoplasm, where they associate with chaperone substrates that require refolding (10, 11). When cells recover from stress, hsc70s transiently concentrate in nuc...

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Chaperones and multitasking proteins in the nucleolus: networking together for survival?

Cited by 35 publications

References 61 publications

Cajal bodies and their role in plant stress and disease responses

Cajal bodies and their role in plant stress and disease responses

Firefly luciferase mutants as sensors of proteome stress

Nucleolar Targeting of the Chaperone Hsc70 Is Regulated by Stress, Cell Signaling, and a Composite Targeting Signal Which Is Controlled by Autoinhibition

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