The essential @entity4357 kinase homologue @entity34057 of @entity375 controls the actin cytoskeleton by activating a GTPase switch consisting of @entity34214 (GTPase), @entity70349 (GEF) and @entity70350 (GAP). We have identified two mutations, rot1-1 and rot2-1, that suppress the loss of @entity34057 and are synthetic-lethal. The wild-type ROT1 and ROT2 genes and a multicopy suppressor, @entity29906 , were isolated by their ability to rescue the rot1-1 rot2-1 double mutant. ROT2 encodes glucosidase II, and ROT1 and @entity29906 encode novel proteins. We present evidence that cell wall defects activate @entity34214 . First, rot1, rot2, @entity29906 , @entity70351 , @entity33909 and fks1 mutations all confer cell wall defects and suppress @entity34057 (ts). Second, destabilizing the cell wall by supplementing the growth medium with 0.005% @entity214 also suppresses a @entity34057 (ts) mutation. Third, disturbing the cell wall with @entity214 or a rot1, rot2, @entity29906 , @entity70351 , @entity33909 or fks1 mutation increases @entity3006 / @entity3007 exchange activity toward @entity34214 . These results suggest that cell wall defects suppress a @entity34057 mutation by activating @entity34214 independently of @entity34057 , thereby inducing @entity34057 -independent polarization of the actin cytoskeleton and cell wall synthesis. Activation of @entity34214 , a subunit of the cell wall synthesis enzyme glucan synthase, by a cell wall alteration would ensure that cell wall synthesis occurs only when and where needed. The mechanism of @entity34214 activation by a cell wall alteration is via the exchange factor @entity70349 and could be analogous to signalling by integrin receptors in @entity1 cells.

Cell wall integrity modulates @entity34214 activity via the exchange factor XXXX .

@entity3007 :: ('MESH:D006160', 'Chemical') :: ['GTP'] @entity1 :: ('9606', 'Species') :: ['mammalian'] @entity70351 :: ('7841', 'Gene') :: ['cwh41'] @entity34214 :: ('856294(Tax:4932)', 'Gene') :: ['RHO1'] @entity3006 :: ('MESH:D006153', 'Chemical') :: ['GDP'] @entity33909 :: ('2619', 'Gene') :: ['gas1'] @entity34057 :: ('853632(Tax:4932)', 'Gene') :: ['tor2', 'TOR2'] @entity29906 :: ('5067', 'Gene') :: ['big1', 'BIG1'] @entity70350 :: ('851997(Tax:4932)', 'Gene') :: ['SAC7'] @entity375 :: ('4932', 'Species') :: ['Saccharomyces cerevisiae'] @entity70349 :: ('851086(Tax:4932)', 'Gene') :: ['ROM2'] @entity4357 :: ('MESH:D010716', 'Chemical') :: ['phosphatidylinositol'] @entity214 :: ('CHEBI:8984', 'Chemical') :: ['SDS']
@entity70349 :: (851086(Tax:4932),Gene) :: ['ROM2']
