REGULATION OF CELL-DIFFERENTIATION BY THE DROSOPHILA JUN KINASE CASCADE

Recent studies have defined a new Drosophila Jun amino-terminal kinase (DJNK) pathway. The first role that has been uncovered for this pathw ay is the control of cell differentiation and morphogenesis during the process of dorsal closure. This phosphorylation cascade has been cons erved during evolution and several reports suggest that it becomes act ivated in response to the action of small GTPases. DJNK signalling imp inges on transcription factors as DJun and Anterior open and eventuall y controls the expression of target genes such as decapentaplegic and puckered. Important progress has been made in the study of the coordin ation of DJNK and Decapentaplegic signalling during dorsal closure and their role in the control of cell shape changes - and possibly cell p olarity - by promoting cytoskeletal changes.