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C2PA is a nuclear protein implicated in the heat shock response
Author(s) -
Hirabayashi Susumu,
Ohno Hideki,
Iida Junko,
Hata Yutaka
Publication year - 2002
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.10279
Subject(s) - pdz domain , biology , microbiology and biotechnology , heat shock protein , claudin , protein family , tight junction , biochemistry , gene
Abstract C2PA is a protein of unknown function that is expressed in spermatocytes. PDZ‐RGS3 is a signaling molecule whose PDZ domain binds Ephrin‐B2 and mediates reverse signaling of this protein. C2PA and PDZ‐RGS3 have identical PDZ domains. To explore the function of C2PA, we compared it with PDZ‐RGS3 with respect to tissue distribution, subcellular localization, and biochemistry. C2PA is expressed only in testis, whereas PDZ‐RGS3 is expressed in various tissues including brain, heart, lung, liver, spleen, kidney, small intestine, skeletal muscles, and testis. These proteins also differ in their subcellular distribution, in that PDZ‐RGS3 is cytosolic while C2PA is exclusively nuclear. C2PA is distributed diffusely in the nucleus and forms a few foci at 37°C. However, when cells are exposed to 42°C, the number of C2PA foci is increased. These heat shock‐induced foci colocalize with CREB‐binding protein and heat shock factor‐1. In contrast, the distribution of PDZ‐RGS3 does not change during heat stress. When overexpressed, C2PA induces heat shock response element (HSE)‐dependent gene transcription, whereas PDZ‐RGS3 does not. These data suggest that the function of C2PA is distinct from that of PDZ‐RGS3, and that C2PA may be involved in the heat shock response in testis. J. Cell. Biochem. 87: 65–74, 2002. © 2002 Wiley‐Liss, Inc.