High impact information on SPC1

• These observations strongly suggest that PP2C enzymes play an important role in the attenuation of Spc1 activity in heat-shocked cells [1].
• However, in heat-shocked cells, Pyp1, the major tyrosine phosphatase that dephosphorylates and inactivates Spc1, is inhibited for its interaction with Spc1, which leads to strong activation of Spc1 [1].
• Thus, transient activation of Spc1 upon heat shock is ensured by differential regulation of threonine and tyrosine phosphorylation [1].
• Interestingly, the Spc1-Hal4 interaction appears to be required for cellular resistance to Ca(2+) but not Na(+) and Li(+) [2].
• Spc1 is most closely related to Saccharomyces cerevisiae Hog1 and mammalian p38 kinases [3].

Biological context of SPC1

• Delta wik1 cells are impaired in stress-induced activation of Spc1 and show a G2 cell cycle delay and osmosensitive growth [4].
• These findings demonstrate that Spc1 promotes expression of genes involved in stress survival and that of regulation may be commonly employed to modulate MAPK signal transduction pathways in eukaryotic species [3].
• Spc1, an osmotic-stress-stimulated mitogen-activated protein kinase (MAPK) homolog in the fission yeast Schizosaccharomyces pombe, is required for the induction of mitosis and survival in high-osmolarity conditions [3].
• Whereas Hog1 is specifically responsive to osmotic stress, we report here that Spc1 is activated by multiple forms of stress, including high temperature and oxidative stress [3].

Anatomical context of SPC1

• In eukaryotic cells, environmental stress signals are transmitted by evolutionarily conserved MAPKs, such as Hog1 in the budding yeast Saccharomyces cerevisiae, Spc1 in the fission yeast Schizosaccharomyces pombe and p38/JNK in mammalian cells [5].

Associations of SPC1 with chemical compounds

• Spc1 is activated by a MAPK kinase homologue, Wis1, and negatively regulated by Pyp1 and Pyp2 tyrosine phosphatases [4].
• Intriguingly, the partial suppression of both high pH sensitivity, and the inactivating effect of NH(4)(+) on leucine transport, seen in pub1-1 point mutants, becomes as complete as seen in pub1Delta backgrounds when cells have concomitantly lost the function of the spc1 stress-activated MAPK [6].

References