Anopheles gambiae laminin interacts with the P25 surface protein of Plasmodium berghei ookinetes

Laminin is a major constituent of the basal lamina surrounding the midgut o f the malaria vectors that has been implicated in the development of the Pl asmodium oocyst. In this report we describe the cloning of the Anopheles ga mbiae gene encoding the laminin gamma1 polypeptide and follow its expressio n during mosquito development. To further investigate the putative role of laminin in the transmission of the malaria parasite wt studied the potentia l binding of the P25 surface protein of Plasmodium berghei using a yeast tn o-hybrid system. Heterodimer formation was observed and does not require an y additional protein factors since purified fusion proteins can also bind e ach other in vitro. Laminin gamma1 also interacts with the paralogue of P25 . namely P28, albeit more weakly, possibly explaining why the two parasite proteins can substitute for each other in deletion mutants. This represents the first direct evidence for molecular interactions between a surface pro tein of the Plasmodium parasite with an Anopheles protein: the strong inter play between laminin gamma1 and P25 suggests: that this pair of proteins ma y function as a receptor;ligand complex regulating parasite development in the mosquito vector. (C) 2001 Elsevier Science B.V. All rights reserved.