Using chromosomal DNA from Kluyveromyces lactis as template and oligodeoxynucleotides designed from conserved regions of various G protein alpha subunits we were able to amplify by the polymerase chain reaction two products of approximately 0.5 kb (P-1) and 0.8 kb (P-2). Sequencing showed that these two fragments share high homology with genes coding for the G alpha subunits from different sources. Using the P-1 fragment as a probe we screened a genomic library from K. lactis and we cloned a gene (KlGPA2) whose deduced amino acid sequence showed, depending on the exact alignment, 62% similarity and 38% identity with Gpa1p and 76% similarity and 63% identity with Gpa2p, the G protein alpha subunits from Saccharomyces cerevisiae. KlGPA2 is a single-copy gene and its disruption rendered viable cells with significantly reduced cAMP level, indicating that this G alpha subunit may be involved in regulating the adenylyl cyclase activity, rather than participating in the mating pheromone response pathway. KlGpa2p shares some structural similarities with members of the mammalian G alpha s family (stimulatory of adenylyl cyclase) including the absence in its N-terminus of a myristoyl-modification sequence.

• PMID: 8896279
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Journal Article | Research Support, Non-U.S. Gov't

Authors

Saviñón-Tejeda AL, Ongay-Larios L, Ramírez J, Coria R

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