Biochemical and functional aspects of GbpC and other roco proteins in Dictyostelium discoideum

PhD ceremony: Mr. W.N. van Egmond, 14.45 uur, Academiegebouw, Broerstraat 5, Groningen

Thesis: Biochemical and functional aspects of GbpC and other roco proteins in Dictyostelium discoideum

Promotor(s): prof. P.J.M. van Haastert

Faculty: Mathematics and Natural Sciences

The Roco family is a group of recently described signaling proteins. One of these proteins is involved in the development of Parkinson’s Disease in humans, but it is not well known how exactly. To gain more knowledge about the functions of Roco proteins, and about the way that they transduce signals in a cell, we have studied functions and biochemical activation mechanisms of Roco proteins in the unicellular slime mold Dictyostelium discoideum. It appeared that some Roco proteins are involved in cell division and the development to a multicellular organism, which is a characteristic process for Dictyostelium. Another protein is involved in chemotaxis and electrotaxis (the movement in the direction of a chemical or electrical signal respectively), which are important processes in the survival strategy of this slime mold. The way in which signals are transduced was studied in two of these Roco proteins. It appeared that the activation mechanisms are highly similar with each other, and also with other described Roco proteins in other organisms; these proteins all share a Roc domain, that after activation transduces an intramolecular signal to a kinase domain. This kinase domain transmits the signal further to another protein, by means of phosphorylation. This thesis describes that Roco proteins have very diverse functions, but the biochemical mechanisms that these proteins use to transduce signals are very conserved in nature.