Forms part of the ribosomal stalk, playing a central role in the interaction of the ribosome with GTP-bound translation factors. Part of the 50S ribosomal subunit. Homodimer, it forms part of the ribosomal stalk which helps the ribosome interact with GTP-bound translation factors. Forms a heptameric L10(L12)2(L12)2(L12)2 complex, where L10 forms an elongated spine to which the L12 dimers bind in a sequential fashion. Belongs to the eukaryotic ribosomal protein P1/P2 family. Was originally thought to originate from S.solfataricus strain P1, but the culture was contaminated with S.acidocaldarius.