DYNAMICS OF INTERMEDIATE FILAMENTS - RECENT PROGRESS AND UNANSWERED QUESTIONS

Intermediate filaments (IFs) have always been considered as the most static and 'skeletal' cellular elements. This view is now changing: new information reveals that IFs exchange subunits at steady-state, that IF networks can be assembled de novo, and that IF proteins are subject to elaborate chemical modification and de-modification during mitosis. I describe below some of the key observations which have made us realize that IFs are dynamic structures. I also discuss some of the remaining questions pertinent to the pathways of IF assembly under in vivo conditions.