Complex sentence: Mellman has served on the council of the American Society for Cell Biology and was the editor-in-chief of the Journal of Cell Biology from 1999-2008, he remains active as a Senior Editor for the journal.
Split into simpler sentences: Mellman has served on the council of the American Society for Cell Biology and was the editor-in-chief of the Journal of Cell Biology from 1999-2008. He remains active as a Senior Editor for the journal.