TheSaccharomyces cerevisiae genes (CMP1 andCMP2) encoding calmodulin-binding proteins homologous to the catalytic subunit of mammalian protein phosphatase 2B

Abstract

Saccharomyces cerevisiae genomic clones that encode calmodulin-binding proteins were isolated by screening a lambda gt11 expression library using 125I-labeled calmodulin as probe. Among the cloned yeast genes, we found two closely related genes (CMP1 and CMP2) that encode proteins homologous to the catalytic subunit of phosphoprotein phosphatase. The presumed CMP1 protein (62,999 Da) and CMP2 protein (68,496 Da) contain a 23 amino acid sequence very similar to those identified as calmodulin-binding sites in many calmodulin-regulated proteins. The yeast genes encode proteins especially homologous to the catalytic subunit of mammalian phosphoprotein phosphatase type 2B (calcineurin). The products of the CMP1 and CMP2 genes were identified by immunoblot analysis of cell extracts as proteins of 62,000 and 64,000 Da, respectively. Gene disruption experiments demonstrated that elimination of either or both of these genes had no effect on cell viability, indicating that these genes are not essential for normal cell growth.

Identification and molecular characterization of the calmodulin‐binding subunit gene (CMP1) of protein phosphatase 2B from Saccharomyces cerevisiae

“…Based on chromosomal blots and low stringency Southern hybridization analyses, we also concluded that there was at least one other CMPI-related gene. In accord with our results, Liu et al (1991) found that disruption of C M P l was not lethal. In addition, they found that disruption of CMP2 was also not lethal in thc presence or absence of a functional C M P l gene.…”

“…This strongly suggests that all these phosphatases have highly conserved functions with great constraints placed on sequence divergence. While the manuscript of this paper was in preparation, another laboratory reported the cloning and sequence of the same yeast gene reported here (Liu et al, 1991). They used I2'I-labeled bovine brain calmodulin to screen a E.gtl1 yeast expression library and identified two sets of overlapping DNA fragments.…”

“…The partial sequence of CMPZ has also recently been reported by Da Cruz e Silva et al (1991). The sequence of CMP2 from Liu et al (1991) is shown in Fig. 6.…”

The interaction between the catalytic A subunit of calcineurin and its autoinhibitory domain, in the yeast two‐hybrid system, is disrupted by cyclosporin A and FK506

“…Two yeast genes, homologous to mammalian calcineurin A catalytic subunits, have been identified. They are CNA1 and CNA2, also known as CMP1 and CMP2 [9,10]. Comparison of the amino acid sequences of Cnalp and Cna2p with that of a mammalian calcineurin A subunit reveals a presumptive calmodulin-binding site and an AID sequence in both the polypeptides [9] (Fig.…”

“…In fact, yeast cells possess two genes, CNA1 and CNA2, homologous to the mammalian A subunit [9,10]. Both the Cnal and Cna2 proteins contain regions which have similarity to the putative AID sequence of the mammalian enzyme [9].…”