The function of small GTPases in cell morphogenesis and migration

Johan Peränen, Doc., Ph. D.

Institute of Biotechnology
Phone: +358-0-191 59588
Fax: +358-0-191 59366>
E-mail: johan dot peranen -at- helsinki dot fi

Small GTP-binding proteins (GTPases) are a large group of proteins involved in the regulation of quite different cellular processes like cell proliferation, differentiation (Ras-, Rap- and Ral-family), nuclear transport (Ran), vesicular transport (Rab-family) and cytoskeleton organization (Rho-family). Aside from controlling above mentioned processes some of the small GTPases have also been implicated in the regulation of cell morphogenesis and migration (Ras- and Rho-proteins). Our group is primarily studying a small GTPase called Rab8. Rab8 belongs to the largest Ras-like small GTPase family, the Rab family, involved in regulating membrane transport. We have recently shown that this molecule regulates cell morphogenesis by promoting cell polarization through reorganization of both actin and microtubules. (Peränen et al., 1996). This actualizes the possible role of membrane dynamics during cell morphogenesis and motility - a subject that has obtained too little attention lately. Our major goals are to: 1) Study the role of Rab8 during cell morphogenesis and motility 2) Determine the connection of Rab8 to the Rho family proteins. 3) Find new effector molecules for Rab8 by using the two-hybrid system.


Katarina Hattula, M.Sc., doctoral student; Jaana Levänen, M.Sc., doctoral student; Johanna Furuhjelm, student and Airi Arffman, technician, M.Sc.

Selected publications

Peränen, J., Laakkonen, P., Hyvönen, M. & Kääriäinen, L. The replicase protein nsP1 is membrane-associated and has affinity to endocytic organelles. Virology 208, 610-620, 1995.

Murata, M., Peränen, J., Schreiner, P., Wieland, F., Kurzchalia, T. & Simons, K. VIP21/caveolin is a cholesterol-binding protein. Proc.Natl.Acad.Sci.USA. 92, 10339-10343, 1995.

Scheiffele, P., Peränen, J. & Simons, K. N-glycans as apical sorting signals in epithelial cells. Nature 378, 96-98, 1995.

Peränen, J., Auvinen, P., Virta, H., Wepf, R., & Simons, K. Rab8 promotes polarized membrane transport through reorganization of actin and microtubules in fibroblasts. J. Cell Biol. 135, 153-167, 1996.

Ulmanen, I., Peränen, J., Tenhunen, J., Tilgman, C., Karhunen, T., Panula, P., Bernasconi, L., Aubry, J. & Lundström, K. Expression and intracellular localization of catechol O-methyltransferase in transfected mammalian cells. Eur. J. Biochem. 243, 452-459, 1997.


The Academy of Finland, Technology Development Centre (TEKES), The University of Helsinki Fund, Wihuri Foundation and the Institute of Biotechnology.

Airi Arffman (airi dot arffman -at- helsinki dot fi)
Updated 2.3.2000