SIGNAL TRANSDUCTION AND CYTOSKELTON

腺苷酸环化酶相关蛋白CAP首先在酿酒酵母中被鉴定，并且幸运的是，在从酵母到人类的许多真核生物中发现了其同源物。酵母CAPs具有三种功能：N -末端结构域作为腺苷酸环化酶结合区，C -末端结构域作为肌动蛋白结合区，中心富含脯氨酸的结构域作为SH 3（Src Homology 3）结合区.在这里，我们报告的cDNA和基因组DNA编码的帽同源物从蘑菇香菇鉴定。Southern杂交结果表明该基因为单拷贝基因.香菇cap基因含有8个内含子和一个开放阅读框，编码518个氨基酸的蛋白质。与酵母CAP的N -末端结构域（27 - 35%同一性）相比，C -末端结构域具有更高的同源性（39 - 46%同一性）.香菇CAP在粟酒裂殖酵母和酿酒酵母中的表达弥补了与内源性CAP的C -末端结构域功能丧失相关的缺陷。通过酵母双杂交试验，我们证明了香菇CAP和粟酒裂殖酵母肌动蛋白之间的相互作用。这一结果和功能互补试验表明蘑菇CAP在C端功能上是保守的.

The adenylyl cyclase - associated protein, CAP,was first identified in Saccharomyces cerevisiae, and succeedingly, its homologs were found in many eukaryotes ranging from yeasts to humans. Yeast CAPs have been found to have three functions : the N - terminal domain as the region for binding adenylyl cyclase, the C - terminal domain as an actin binding domain, and the central proline - rich domainas the SH3 (Src Homology 3) binding region. Here, we report the identification of a cDNA and genomic DNA encoding a CAP homolog from mushroom Lentinus edodes. Southern blotting results suggest it to be a single - copy gene. The L.edodes cap gene contains 8 introns and an open reading frame encoding a 518 amino acid protein. The C - terminal domain shares higher homology (39 - 46 % identity) compared with the N - terminal domain (27 - 35 % identity) with yeast CAPs. Expression of the L.edodes CAP in both S.pombe and in S.cerevisiae complemented defects associated with loss of the C - terminal domain function of endogenous CAP.By using yeast two - hybrid assay, we demonstrated the interaction between the L.edodes CAP and S.pombe actin. This result andfunctional complementation test indicate CAP from mushroom is conserved in terms of the C - terminal function of CAP.