Functional characteristics of mortalin

Abstract

Mortalin, also termed mitochondria heat shock protein 70 (mthsp70), peptide binding protein 74 (PBP74), or glucose regulated protein 75 (Grp75), is a member of the Hsp70 chaperone family and has been shown to possess unique functional characteristics in a number of different subcellular loci. Functional roles can be classified into two major classes based upon subcelluar location. The first class of functions involve those that occur in the mitochondrion which include participation in the import of nuclear-encoded cytoplasmically-delivered proteins, nascent protein folding and protein degradation within the mitochondrion, and interaction with submitochondrial constituents. The second class involves extramitochondrial functions that include interaction with protein 53 (p53), centrosomes, growth factors, immune system constituents, proteins of the endoplasmic reticulum, and metabolic constituents. The purpose of this review is to describe some of the major functional roles of mortalin action in various subcellular compartments. Further, evaluation of pathology on mortalin proteomic status will be examined in an effort to highlight the potential importance of mortalin in disease initiation and progression.