The function of GNL3L (G protein nucleolar 3 like, Ensembl gene identifier ENSG00000130119) is as follows. Stabilizes TERF1 telomeric association by preventing TERF1 recruitment by PML. Stabilizes TERF1 protein by preventing its ubiquitination and hence proteasomal degradation. Does so by interfering with TERF1-binding to FBXO4 E3 ubiquitin-protein ligase. Required for cell proliferation. By stabilizing TRF1 protein during mitosis, promotes metaphase-to-anaphase transition. Stabilizes MDM2 protein by preventing its ubiquitination, and hence proteasomal degradation. By acting on MDM2, may affect TP53 activity. Required for normal processing of ribosomal pre-rRNA. Binds GTP. {ECO:0000269|PubMed:16251348, ECO:0000269|PubMed:17034816, ECO:0000269|PubMed:19487455, ECO:0000269|PubMed:21132010}.