The dominant field of interest in our laboratory is cell morphogenesis and related regulatory processes in plant cells. In plants, which cells do not migrate, morphogenesis results from two processes - oriented cell division and differential cell growth. In our work, we focus on intracellular molecular mechanisms driving cellular morphogenesis “from inside” - as in germinating pollen tubes or developing pollen embryos. Proteins participating in these mechanisms are, despite of the major differences in cell structure and behaviour, often very similar to those found in the fungal and animal kingdoms (Žárský and Cvrčková, 1997; Cvrčková et al., 2001).
Using pollen cDNA library screen and RT-PCR approach, we have identified several members of Ras related GTPase family expressed in tobacco pollen. Besides the Rab family members participating in vesicle trafficking we have isolated also Rho/Rac GTPase (in plants called Rop) involved probably in actin network organization in pollen grains and germinating pollen tubes. Using GTP/GDP microinjetion into pollen tubes we have shown that GTPases regulate cell polarity (Eliáš et al., 2001). Recently we have cloned and partially characterized tobacco pollen expressed PLDs as putative GTPase effectors. We have shown that phosphatidic acid – product of PLD activity – is an important component of the process of plant cell expansion (Potocký et al., 2003). Our laboratory closely collaborates on PLDs research with colleagues from the Institute of Chemistry (Dr. O. Valentová).
We have isolated plant Rab GDP dissociation inhibitor (Rab GDI) by complementation of Saccharomyces cerevisiae ts mutant sec19-1 with Arabidopsis thaliana cDNA library (Žárský et al. 1997) and currently we focus on Rab geranylgeranyl transferase - a complex posttranslationally modifying C-termini of Rab GTPases by a hydrophobic geranylgeranyl chain. In collaboration with colleagues from the Department of Plant Physiology, Charles University (Dr. Fatima Cvrčková) we work on the characterization of plant formin family involved in F-actin formation and related processes. We focus on the characterization of plant homologues of the exocyst complex (participates in other eukaryots in localization of exocytosis) and PLD function in plant cell expansion (Eliáš et al., 2003; Potocký et al., 2003).
Čeština
English
