GSBS Student Publications

GSBS Program

Biochemistry & Molecular Pharmacology

Publication Date


UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Biochemistry and Molecular Biology; Program in Molecular Medicine; Department of Physiology,

Document Type



Life Sciences | Medicine and Health Sciences


The mitogen-activated protein (MAP) kinase signal transduction pathway represents an important mechanism by which growth factors regulate cell function. Targets of the MAP kinase pathway are located within several cellular compartments. Signal transduction therefore requires the localization of MAP kinase in each sub-cellular compartment that contains physiologically relevant substrates. Here, we show that serum treatment causes the translocation of two human MAP kinase isoforms, p40mapk and p41mapk, from the cytosol into the nucleus. In addition, we report that p41mapk (but not p40mapk) is localized at the cell surface ruffling membrane in serum-treated cells. To investigate whether the protein kinase activity of MAP kinase is required for serum-induced redistribution within the cell, we constructed mutated kinase-negative forms of p40mapk and p41mapk. The kinase-negative MAP kinases were not observed to localize to the cell surface ruffling membrane. In contrast, the kinase-negative MAP kinases were observed to be translocated to the nucleus. Intrinsic MAP kinase activity is therefore required only for localization at the cell surface and is not required for transport into the nucleus. Together, these data demonstrate that the pattern of serum-induced redistribution of p40mapk is different from p41mapk. Thus, in addition to common targets of signal transduction, it is possible that these MAP kinase isoforms may differentially regulate targets located in distinct sub-cellular compartments.

DOI of Published Version



J Cell Biol. 1993 Sep;122(5):1089-101.

Journal/Book/Conference Title

The Journal of cell biology

Related Resources

Link to article in PubMed

PubMed ID


Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License.