Posttranslational arginylation of soluble rat brain proteins after whole body hyperthermia

Abstract

We have previously reported the posttranslational addition of [14C]-arginine in the N-terminus of several soluble rat brain proteins. One of these proteins was identified as the microtubule-associated protein, the stable tubule only polypeptide (STOP). However, despite the fact that the biological significance of arginylation is not completely understood, some evidence associates it with proteolysis via the ubiquitin pathway. Since this degradative via is exacerbated as a response to stress, we studied in vitro the posttranslational [14C]-arginylation of cytosolic brain proteins of rats subjected to hyperthermia in vivo. Immediately after subjecting the animals to hyperthermia, a minor reduction (16%) in the acceptor capacity of [14C]-arginine into proteins was observed in comparison with animals maintained at 28 degrees C. However, in the animals allowed to recover for 3 h, an increase (46%) in the arginylation was observed concomitantly with a significant accumulation of the heat shock protein (70 kDa; hsp 70) when compared to the control animals. These findings suggest that the posttranslational arginylation of proteins participate in the heat shock response. The STOP protein of the soluble brain fraction of control animals, which in Western blot appears as a doublet band (125 and 130 kDa, respectively), is seen, after the hyperthermic treatment, as a single band of 125 kDa. The amount of 125 kDa protein, as well as the in vitro incorporation of [14C]-arginine, increases after hyperthermia in comparison with control animals. Following hyperthermic treatment, we observed a decrease in the amount of in vivo [35S]-methionine-labeled brain proteins. We speculate that, as observed for STOP protein, the increase in the degradation of protein that occurs in hyperthermia, would produce an increase in the amount of arginine acceptor proteins.

Arginyltransferase regulates alpha cardiac actin function, myofibril formation and contractility during heart development

“…While in yeast Ate1 gene is not essential for cell viability, Ate1 knockout in mice results in embryonic lethality and severe defects in cardiovascular development and angiogenesis (Kwon et al, 2002). Multiple proteins are arginylated in vivo (Bongiovanni et al, 1999; Decca et al, 2006a; Decca et al, 2006b; Eriste et al, 2005; Fissolo et al, 2000; Hallak and Bongiovanni, 1997; Kopitz et al, 1990; Lee et al, 2005), including 43 protein targets isolated from different mouse cells and tissues (Wong et al, 2007). …”

Identification of mammalian arginyltransferases that modify a specific subset of protein substrates

“…Evidence indicates that many proteins are arginylated in vivo (9)(10)(11)(12) and that ATE1 functions as a component of the ubiquitin (Ub)-dependent N-end rule pathway that relates the metabolic stability of a protein to the identity of its N-terminal residue (13). Although some proteins are, indeed, destabilized by the addition of N-terminal arginine (11,13,14), the exact relationship between arginylation and Ub protein degradation in vivo remains to be determined.…”

Protein Arginylation, a Global Biological Regulator that Targets Actin Cytoskeleton and the Muscle

“…However, later studies in other biological systems demonstrated that this was, in fact, far from true. A series of later studies implicated arginylation in regulation of embryogenesis (Kwon et al, ) aging (Lamon and Kaji, ; Kaji et al, ), stress and heat shock (Rao and Kaji, 1977; Lamon et al, ; Bongiovanni et al, ), regenerative processes (Tanaka and Kaji, ; Chakraborty and Ingoglia, ; Xu et al, ; Wang and Ingoglia, ), and protein degradation in the skeletal muscle (Solomon et al, ). In mice, Ate1 knockout results in embryonic lethality, abnormal cardiac morphogenesis, and impaired angiogenesis.…”