Family With Sequence Similarity 53, Member B (FAM53B)

Smp which is homologous to the human FAM53B gene. smp was expressed in actively proliferating cells of the CNS throughout embryogenesis. It belongs to a family of vertebrate-specific genes with no characterized biochemical domains. FAM53B bound 14-3-3 chaperones, as well as SKIIP proteins, adaptor proteins connecting DNA-binding proteins to modulators of transcription. smp inactivation with morpholinos led to delayed epiboly and reduced embryonic size. Absence of Smp activity did not induce apoptosis, but resulted in a reduced cell proliferation rate and enlarged blastomeres. Moreover, smp was shown to control the expression of the pluripotency-associated oct4/pou5f1 gene. In addition, the human homolog FAM53B binds to the SKIIP protein, known to modulate the activity of transcriptional regulators implicated in cell proliferation.