In vitro effects on microtubule dynamics of purified Xenopus M phase-activated MAP kinase

Abstract

The protein kinase MAP kinase, also called MAP2 kinase, is a serine/threonine kinase whose activation and phosphorylation are induced by a variety of mitogens, and which is thought to have a critical role in a network of protein kinases in mitogenic signal transduction. A burst in kinase activation and protein phosphorylation may also be important in triggering the dramatic reorganization of the cell during the transition from interphase to mitosis. The interphase-metaphase transition of microtubule arrays is under the control of p34cdc2 kinase, a central control element in the G2-M transition of the cell cycle. Here we show that a Xenopus kinase, closely related to the mitogen-activated mammalian MAP kinase, is phosphorylated and activated during M phase of meiotic and mitotic cell cycles, and that the interphase-metaphase transition of microtubule arrays can be induced by the addition of purified Xenopus M phase-activated MAP kinase or mammalian mitogen-activated MAP kinase to interphase extracts in vitro.

Inhibition of c-Jun DNA binding by mitogen-activated protein kinase.

“…p42 MAP kinase was relatively insensitive to staurosporine (no detectable inhibition at 500 nM) but sensitive to the structurally similar inhibitor K252a (90% inhibition at 200 nM). The substrate specificity, sensitivity to inhibitors, and kinetic properties of our purified Xenopus p42 MAP kinase are consistent with those reported by Gotoh et al (199la) and Barrett et al (1992) for Xenopus p42 MAP kinases, with those reported by Rossomando et al (1991) and Gotoh et al (1991a) Figure 1, c-Jun was efficiently phosphorylated by partially purified MAP kinase (OA27). Several observations argue that the observed Jun kinase activity is due to p42 MAP kinase rather than some contaminating kinase: both the Jun kinase and MBP kinase activities were inhibited by K-252a (-90% inhibition of both activities at 200 nM; 100% inhibition at 200,uM; Figure 1) but not by staurosporine (500 nM); both the Jun kinase and MBP kinase activities were inhibited by synthetic peptides derived from the sequence around the Jun phosphorylation site (14 mM PPLAPID, Figure 1; vide infra); and both the Jun kinase and MBP kinase activities were immunoprecipitated by antiserum (Figure 2A).…”

“…Both kinases are expressed in a wide variety of tissues and cell lines (Boulton and Cobb, 1991), and both are activated in response to diverse stimuli. The two kinases exhibit similar substrate preferences in vitro (Boulton et al, 1991a;Gonzalez et al, 1991;Gotoh et al, 1991a;Rossomando et al, 1991;Barrett et al, 1992).…”

Isolation and Expression Pattern of Human Unc-33-Like Phosphoprotein 6/Collapsin Response Mediator Protein 5 (Ulip6/CRMP5): Coexistence with Ulip2/CRMP2 in Sema3A- Sensitive Oligodendrocytes

“…Sema3A, via Ulip2/CRMP2 or Ulip6/CRMP5, may act on the dynamics of microtubules, leading to the decrease in process extension. Several results support this hypothesis: (1) microtubules are present in oligodendrocytes and reflect oligodendrocyte function (Lunn et al, 1997), (2) Ulip2/CRMP2 mediates the dynamics of microtubules , and (3) protein kinase, which could phosphorylate the numerous phosphorylation sites of the Ulip/CRMPs, regulates oligodendrocyte process extension (Stariha et al, 1997) and can affect microtubule dynamics (Gotoh et al, 1991). Although these results show that oligodendrocytes are sensitive to Sema3A, other signals might also be mediated by Ulip/CRMPs (Wang and Strittmatter, 1997).…”

Phosphorylation of Microtubule-associated Proteins MAP2 and MAP4 by the Protein Kinase p110mark

“…XMAP from Xenopus eggs, Faruki and Karsenti (1994)). Regarding kinases, cdc2 and MAP kinases were suggested as potential triggers of microtubule reorganization (Gotoh et al, 1991;Verde et al, 1992;Lieuvin et al, 1994;Ookata et al, 1995). However, it remains to be seen whether these kinases act directly or via other intermediate steps.…”