Cellular and biochemical events in mammalian cells during and after recovery from physiological stress.

Abstract

Abstract. We have examined and compared a number of cellular and biochemical events associated with the recovery process of rat fibroblasts placed under stress by different agents. Metabolic pulse-labeling studies of cells recovering from either heat-shock treatment, exposure to sodium arsenite, or exposure to an amino acid analogue of proline, L-azetidine 2-carboxylic acid, revealed interesting differences with respect to the individual stress proteins produced, their kinetics of induction, as well as the decay in their synthesis during the recovery period. In the initial periods of recovery, the major stress-induced 72-kD protein accumulates within the altered nucleoli in close association with the pre-ribosomal-containing granular region. During the later times of recovery from stress, the nucleoli begin to regain a normal morphology, show a corresponding loss of the 72-kD protein, and the majority of the protein now begins to accumulate within the cytoplasm in three distinct locales: the perinuclear region, along the perimeter of the cells, and finally in association with large phase-dense structures. These latter structures appear to consist of large aggregates of phase-dense material with no obvious encapsulating membrane. More interestingly we show, using doublelabel indirect immunofluorescence analysis, that much of the perinuclear and cell perimeter-distributed 72-kD protein coincides with the distribution of the cytoplasmic ribosomes. We discuss the possible implications of the presence of the 72-kD stress proteins within the pre-ribosomal-containing granular region of the nucleolus as well as its subsequent colocalization with cytoplasmic ribosomes in terms of the translational changes which occur in cells both during and after recovery from physiological stress.A organisms from the simplest prokaryotes, yeast, plants, on up to higher eukaryotes respond in a remarkably similar manner to abrupt changes in their environmental circumstance. This apparent defensive mechanism, classically termed the heat-shock response, is now more commonly referred to as the stress response owing to the wide variety of different agents that elicit basically the same cellular changes as those observed after hyperthermic treatment (for reviews see references 3, 8, and 25). Interestingly, the most obvious commonality amongst the various agents that induce the stress response is their ability to promote the accumulation in the cell of abnormal or denatured proteins. The general theme of the stress response in all organisms is the rapid and almost exclusive synthesis of a small number of proteins, the so-called heat-shock or stress proteins, and a corresponding decreased production of most other cellular polypeptides. While considerable work has resulted in identifying the stress proteins in terms of their apparent molecular size, little has been established regarding their mode of action in the cell. However, a recent burst of activity from many laboratories working at the molecular, cellular, and biochemical levels has recen...

Heat Shock Protein hsp72 Induction in Cortical and Striatal Astrocytes and Neurons following Infarction

“…Their brains were removed, postfixed for 4 h, and sectioned (50 ,.., m) on a vibratome. The sections were reacted for the induc ible hsp72 using a monoclonal antibody (sold by Amer-,sham, Arlington Heights, IL, U.S.A.) developed and characterized by Welch and Suhan (1986) that reacts with one major protein (presumptive hsp72) and either a break down product or another minor protein on Western blots (Vass et aI., 1988).…”

Inactivation of Parkin by Oxidative Stress and C-terminal Truncations

“…The mouse monoclonal antibody specific for inducible Hsp72 (C92) and the mouse monoclonal antibody N27, which identifies both the inducible (Hsp72) and the constitutive form (Hsp73) of Hsp70, have been described previously (12).…”

Interaction of canine distemper virus nucleocapsid variants with 70K heat-shock proteins

“…SDS-PAGE analysis of this material demonstrated a heterogeneous population of proteins, with prominent representation of a 70K band. Samples were examined by Western blot analysis (Oglesbee et al, 1989) using polyclonal canine anti-CDV antibody, mouse monoclonal antibody (N27) with specific reactivity to primate 70K hsps (72K and 73K hsps as well as the major 70K hsp degradation products 0000-9240 © 1990 SGM are detected by this reagent; Riabowol et al, 1988), and mouse monoclonal antibody (C92) with specific reactivity to primate 72K hsp (Welch & Suhan, 1986). Analysis of NC variant total protein, using canine CDV convalescent serum as a source of primary antibody, highlighted viral N and P proteins but not the 70K species present in L-NC and Df-NC variants ( Fig.…”