Cystathionine beta-synthase, a key enzyme for homocysteine metabolism, is preferentially expressed in the radial glia/astrocyte lineage of developing mouse CNS.

Cystathionine beta-synthase (CBS; EC 4.2.1.

MOCA induces membrane spreading by activating Rac1.

The modifier of cell adhesion protein (MOCA), or Dock3, initially identified as presenilin-binding protein (PBP), belongs to the Dock180 family of proteins and is localized specifically in neurons. Here we demonstrate that MOCA binds to Rac1 and enhances its activity, which leads to the activation of c-Jun NH(2)-terminal kinase (JNK) and causes changes in cell morphology. Farnesylated MOCA, which is localized in the plasma membrane, enhances the activation of Rac1 and JNK more markedly than wild-type MOCA, and cells expressing farnesylated MOCA show flattened morphology similar to those expressing a constitutive active mutant of Rac1, Rac1Q61L.