Mating factor

Featherstone, C., 1990. An ATP-driven pump for secretion of yeast mating factor. Trends in Biochemical Sciences 15 169—170. 

Murray and Hunt, 1993). Cyclins, kinases, and phosphatases that regulate the passage of the cell through the G] — S phase transition are all present in mammals, invertebrates, and plants (Solomon, 1993 Doonan and Fobart, 1997 Zavitz and Zipursky, 1997). However, multicellular eukaryotes contain multiple orthologs of yeast cell cycle proteins they initiate proliferation via growth factors, rather than, for example, yeast mating factors, and they possess additional checkpoint controls and repair pathways. 

Saccharomyces cerevisiae Synthetic HRP C gene fused in-frame to pre-pro a-mating factor. Constitutive and inducible promoters tried. Low Low levels of h3rperglycosylated enzyme secreted yield approx. 50 xg liter" (71, 72). 

Thyrotropin-releasing hormone (TRH) Vasoactive intestinal peptide Vasopressin Yeast mating factors... 

Sexual conjugation in yeast is also induced by pheromones (mating factors).325-327 Yeast cells of mating type a synthesize the 12-residue mating factor a which contains a C-terminal cysteine methyl ester S-alkylated with a frans,frans-farnesyl group (Table 30-5). Cells of type a synthesize a 13-residue factor ol 327a Cells are attracted to the pheromone produced by cells of the opposite type. The tremerogens, sex hormones of certain basidiomycetes, have related structures (Table 30-5)328... 

Yeast mating factor a 12 YIIKGV(L)FWDPAC-OCH3 farnesylb... 

The first evidence for the existence of the methylation of a prenylated peptidyl substrate was found in two jelly fungi, Tremella mesenterica and Tremella brasiliensis [30,31]. These peptide sequences are similar to the a-mating factor found in Saccharomyces cerevisiae, which is also prenylated at the C-terminus and contains an a-carboxyl methyl ester [32]. The gene product of the STEM in S. cerevisiae was found to be responsible for the methylation event for the a-factor-mating pheromone and the enzymatic activity of this methyltransferase was found only in the cellular membrane fractions [33,34]. Further analyses of Stel4p via epitope tagging determined that the enzyme is localized to the ER membrane and possesses six transmembrane segments, with majority of the enzyme exposed to the cytosol [35,36]. 

The carboxyl terminal four amino acids constitute a CAAX sequence (where A is any aliphatic amino acid and X is any amino acid) that is highly conserved among all ras and ras-related genes. This sequence is present not only in ras and related proteins but also in the carboxyl terminus of other proteins, including the o and Y-subunits of several heterotrimeric G-proteins, nuclear lamins and unprocessed yeast alpha mating factor. This motif has been shown to be responsible for carboxyl terminal modification via isoprenylation for attachment of ras (and other proteins) to the irmer leaflet of the plasma membrane (Bimbaumer, Bimbaumer, 1995 Khosravi-Far, Der, 1994). 

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