Open AccessGerm cell‐specific heat shock protein 105 binds to p53 in a temperature‐sensitive manner in rat testis
Author(s) -
Kumagai Jin,
Fukuda Jun,
Kodama Hideya,
Murata Masanori,
Kawamura Kazuhiro,
Itoh Hideaki,
Tanaka Toshinobu
Publication year - 2000
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1033.2000.01336.x
Subject(s) - heat shock protein , cytoplasm , immunoprecipitation , germ cell , nucleus , biology , microbiology and biotechnology , suppressor , hsp70 , gene , biochemistry
Heat shock protein (HSP)105 is a testis‐specific and HSP90‐related protein. The aim of this study was to explore the functions of HSP105 in the rat testis. Signals of HSP105 were detected immunohistochemically in the germ cells and translocated from the cytoplasm to the nucleus at 2 days after experimental induction of cryptorchidism. In cultured testicular germ cells, a significant increase in the expression of HSP105 in response to heat stress (37 °C) was detected in the insoluble protein fractions. Several binding proteins were isolated from rat testis using a HSP105 antibody immunoaffinity column, and p53, the tumor suppressor gene product, was copurified with these. Furthermore, immunoprecipitation using antibodies to p53 led to coprecipitation of HSP105 together with p53 after culturing germ cells at 32.5 °C, but not at 37 or 42 °C. In conclusion, HSP105 is specifically localized in the germ cells and may translocate into the nucleus after heat shock. HSP105 is suggested to form a complex with p53 at the scrotal temperature, and dissociate from it at suprascrotal temperatures. At scrotal temperature, HSP105 may thus contribute to the stabilization of p53 proteins in the cytoplasm of the germ cells, preventing the potential induction of apoptosis by p53.