KONJAC1 and 2 Are Key Factors for XXXX -Mannose Generation and Affect @entity620 and Glucomannan Biosynthesis in @entity958 .

@entity1 @entity958 @entity620 @entity27965 @entity4241 @entity3006 @entity3913 @entity4334 @entity7943
UNASSIGNED: @entity1 are unable to synthesize @entity620 ( @entity7943 ), yet it is required as a cofactor in many critical biochemical reactions. The majority of @entity1 dietary @entity7943 is obtained from plants. In @entity958 , a @entity3006 - @entity3913 pyrophosphorylase (GMPP), @entity27965 ( @entity27965 ), catalyzes a rate-limiting step in @entity7943 synthesis: the formation of @entity3006 - @entity1 . In this study, we identified two @entity4334 sugar pyrophosphorylase-like proteins, KONJAC1 (KJC1) and KJC2, which stimulate the activity of @entity27965 . The kjc1kjc2 double mutant exhibited severe @entity4241 , indicating that KJC proteins are important for growth and development. The kjc1 mutation reduced GMPP activity to 10% of wild-type levels, leading to a 60% reduction in @entity7943 levels. On the contrary, overexpression of KJC1 significantly increased GMPP activity. The kjc1 and kjc1kjc2 mutants also exhibited significantly reduced levels of glucomannan, which is also synthesized from @entity3006 - @entity1 . Recombinant KJC1 and KJC2 enhanced the GMPP activity of recombinant @entity27965 in vitro, while KJCs did not show GMPP activity. Yeast two-hybrid assays suggested that the stimulation of GMPP activity occurs via interaction of KJCs with @entity27965 . These results suggest that KJCs are key factors for the generation of @entity3006 - @entity1 and affect @entity7943 level and glucomannan accumulation through the stimulation of @entity27965 GMPP activity.
