9.B.293.  The Prokaryotic Sybindin (Sybindin) Family 

This is a small family of proteins derived from uncultured archaea.  Sybindin is a physiological syndecan-2 ligand on dendritic spines, the small protrusions on the surface of dendrites that receive the vast majority of excitatory synapses.  The archaeal proteins may be related to the glycosyl transferases of family 9.B.142, subfamily 3.