The yeast phosphatidylinositol kinase homolog TOR2 activates RHO1 and RHO2 via the exchange factor ROM2.
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Schmidt A, Bickle M, Beck T, Hall MN
The yeast phosphatidylinositol kinase homolog TOR2 activates RHO1 and RHO2 via the exchange factor ROM2.
Cell. 1997 Feb 21;88(4):531-42. doi: 10.1016/s0092-8674(00)81893-0.
- PubMed ID
- 9038344 [ View in PubMed]
- Abstract
The Saccharomyces cerevisiae phosphatidylinositol kinase homolog TOR2 is required for organization of the actin cytoskeleton. Overexpression of RHO1 or RHO2, encoding Rho-like GTPases, or ROM2, encoding a GDP/GTP exchange factor for RHO1 and RHO2, suppresses a tor2 mutation. Deletion of SAC7, a gene originally identified as a suppressor of an actin mutation, also suppresses a tor2 mutation. SAC7 is a novel GTPase-activating protein for RHO1. ROM2 exchange activity is reduced in a tor2 mutant, and overexpression of ROM2 lacking its PH domain can no longer suppress a tor2 mutation. Thus, TOR2 signals to the actin cytoskeleton through a GTPase switch composed of RHO1, RHO2, ROM2, and SAC7. TOR2 activates this switch via ROM2, possibly via the ROM2 PH domain.