Jarczowski Franziska, Jahreis Günther, Erdmann Frank, Schierhorn Angelika, Fischer Gunter, Edlich Frank
Max Planck Research Unit for Enzymology of Protein Folding, Weinbergweg 22, D-06120 Halle/Saale, Germany.
J Biol Chem. 2009 Jan 9;284(2):766-73. doi: 10.1074/jbc.M709779200. Epub 2008 Nov 10.
FKBP36 has been previously shown to be a crucial factor in spermatogenesis because of its interplay with the synaptonemal complex protein SCPI. Here we show that beyond this function, FKBP36 forms complexes with glyceraldehyde-3-phosphate dehydrogenase (GAPDH; EC 1.2.1.12) and Hsp90. Both proteins bind independently to different sites of the FKBP36 tetratricopeptide repeat domain. The interaction between FKBP36 and GAPDH directly inhibits the catalytic activity of GAPDH. In addition, FKBP36 expression causes a significant reduction of the GAPDH level and activity in COS-7 cells. Particularly in the cytosolic fraction, GAPDH was depleted by FKBP36 expression. Thus, FKBP36 diminishes GAPDH activity by direct interaction and down-regulation of GAPDH, which represents a previously unknown mechanism of GAPDH regulation and a novel function of FKBP36 in testis-specific signaling.
此前研究表明，由于FKBP36与联会复合体蛋白SCPI相互作用，它在精子发生过程中是一个关键因素。在此我们发现，除了这一功能外，FKBP36还与甘油醛-3-磷酸脱氢酶（GAPDH；EC 1.2.1.12）和热休克蛋白90形成复合体。这两种蛋白均独立结合至FKBP36四肽重复结构域的不同位点。FKBP36与GAPDH之间的相互作用直接抑制了GAPDH的催化活性。此外，FKBP36的表达导致COS-7细胞中GAPDH水平和活性显著降低。特别是在胞质部分，FKBP36的表达使GAPDH耗竭。因此，FKBP36通过直接相互作用和下调GAPDH来降低其活性，这代表了一种此前未知的GAPDH调节机制以及FKBP36在睾丸特异性信号传导中的新功能。
