Forms part of the ribosomal stalk which helps the ribosome interact with GTP-bound translation factors. Is thus essential for accurate translation. Homodimer. Part of the ribosomal stalk of the 50S ribosomal subunit. Forms a multimeric L10(L12)X complex, where L10 forms an elongated spine to which 2 to 4 L12 dimers bind in a sequential fashion. Binds GTP-bound translation factors. Two isoforms seem to exist. One is probably dimethylated on Lys-69 and monomethylated on Lys-86 while the other is probably acetylated or trimethylated on both Lys-86 and Lys-89. Belongs to the bacterial ribosomal protein bL12 family.