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Review
. 2002 Jul;7(3):309-16.
doi: 10.1379/1466-1268(2002)007<0309:ahfcmm>2.0.co;2.

An Hsp70 family chaperone, mortalin/mthsp70/PBP74/Grp75: what, when, and where?

Renu Wadhwa  1 , Kazunari Taira, Sunil C Kaul
Affiliations
Review

An Hsp70 family chaperone, mortalin/mthsp70/PBP74/Grp75: what, when, and where?

Renu Wadhwa et al. Cell Stress Chaperones. 2002 Jul.

Abstract

Mortalin/mthsp70/PBP74/Grp75 (called mortalin hereafter), a member of the Hsp70 family of chaperones, was shown to have different subcellular localizations in normal and immortal cells. It has been assigned to multiple subcellular sites and implicated in multiple functions ranging from stress response, intracellular trafficking, antigen processing, control of cell proliferation, differentiation, and tumorigenesis. The present article compiles and reviews information on the multiple sites and functions of mortalin in different organisms. The relevance of its differential distributions and functions in normal and immortal cell phenotypes is discussed.

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Figures

Fig 1.
Fig 1.
Protein sequence comparisons of human and mouse mortalins
Fig 2.
Fig 2.
Lifespan extension of normal human lung fibroblasts by over expression of mouse (mot-2) and human (hmot-2A and hmot2B) mortalins in a mammalian expression vector, pSRα. hmot-2A and hmot-2B are complementary deoxyribonucleic acid isolates from HT1080 (human fibrosarcoma assigned to complementation group A of immortalization) and HeLa (human cervical carcinoma assigned to complementation group B of immortalization) cells, respectively. The level of expression of mortalin was slightly higher in hmot-2B–expressing cells than in the mot-2– or hmot-2A–expressing cells (experimental and technical details described in Kaul et al 2000b)
Fig 3.
Fig 3.
(A) Abrogation of nuclear translocation of p53 by mot-2. NIH 3T3 cells were microinjected with green fluorescence protein (GFP)-tagged mot-2 (green fluorescence) and serum-starved for 24 hours to induce nuclear translocation of p53 protein. Note that the cells microinjected with mot-2 (green fluorescence) lacked nuclear p53 (red fluorescence). Similar results were obtained by using N- or C-terminal GFP fusion (experimental and technical details described in Wadhwa et al 1998). (B) Nuclear translocation of p53 (green) in MKT-077–treated human breast carcinoma (MCF7) cells and mouse immortal fibroblasts (NIH 3T3) (Wadhwa et al 2000). Control and MKT-077–treated MCF7 and NIH 3T3 cells were double stained for mortalin (red) and p53 (green). Note that only a negligible number of cells showed nuclear p53 in control cells; MKT-077–treated culture exhibited nuclear p53 in more than 80% of cells
Fig 4.
Fig 4.
A model showing multiple subcellular sites, binding partners, and functions of mortalin
See this image and copyright information in PMC

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