Signal Transduction Pathways and Heterotrimeric G Proteins

Fungal Spore Germination: Insights from the Molecular Genetics ofAspergillus nidulansandNeurospora crassa

“…Two N. crassa genes encoding a subunits of heterotrimeric G proteins have been isolated from N. crassa (Turner and Borkovich, 1993). Gna-1 is a member of the Gi family that appears to play a role in cell proliferation and cell differentiation while Gna-2 is another member of the Gi family that appears to be required for cell viability and may be important for spore germination in N. crassa (Borkovich, 1996). However, recent analysis of the A. nidulans FadA Ga subunit that is more than 90% identical to Gna-2 has demonstrated a role in the control of proliferation rather than in the initiation of spore germination in A. nidulans (Yu et al, 1996).…”

GTP-binding proteins in plants

“…They comprise a large gene family mediating a vast array of signalling processes in all eukaryotes [13,14], serving as a bridge between heptahelical GPCRs and effectors such as phospholipases, adenylate cyclases, phosphodiesterases, ion channels and protein kinases. Binding of an extracellular ligand to a GPCR alters the conformation of the receptor molecule, which promotes its association with an intracellular heterotrimeric G protein.…”

A G Protein Alpha Subunit fromCochliobolus heterostrophusInvolved in Mating and Appressorium Formation

“…A particular G protein can be uniquely involved with one set of receptor/effector molecules or it can be promiscuous, transducing signals from two or more activated receptors (Neer, 1995). Some alpha subunits of G proteins are highly conserved among higher and lower eukaryotes (Borkovich, 1996), a feature that has facilitated the cloning of genes encoding them, as evidenced by reports covering a variety of different fungi, e.g., Saccharomyces cerevisiae (Dietzel and Kurjan, 1987;Miyajima et al, 1987;Nakafuku et al 1988), Schizosaccharomyces pombe (Obara et al, 1991), Candida albicans (Sadhu et al, 1992), Cryptococcus neoformans (Tolkacheva et al, 1994), Coprinus congregatus (Kozak et al, 1995), Kluyveromyces lactis (Savinon Tejeda et al, 1996), Neurospora crassa (Baasiri et al, 1997;Ivey et al, 1996), Aspergillus nidulans (Yu et al, 1996), Cryphonectria parasitica (Gao and Nuss, 1996), Pneumocystis carinii (Smulian et al, 1996), Magnaporthe grisea (Liu and Dean, 1997), Ustilago maydis (Regenfelder et al, 1997), and Ustilago hordei (Lichter and Mills, 1997).…”