Mitochondria, molecular chaperone proteins and the in vivo assembly of microtubules

Two proteins, P1 and P2, which are specifically altered in mammalian cell mutants resistant to antimitotic drugs, have been identified as the homologs of two members of the class of proteins known as molecular chaperones. P1 is localized in mitochondria and P2-related proteins are involved in the translocation of proteins to mitochondria. To account for these and a number of other observations, a new model for in vivo microtubule assembly is proposed.