La Ribonucleoprotein Domain Family, Member 5 (LARP5)

LARP4B, a thus far uncharacterized member of the LARP family. LARP4B is a cytosolic protein that accumulates upon arsenite treatment in cellular stress granules. Biochemical experiments further uncovered an interaction of LARP4B with the cytosolic poly(A) binding protein 1 (PABPC1) and the receptor for activated C Kinase (RACK1), a component of the 40S ribosomal subunit. Under physiological conditions, LARP4B co-sedimented with polysomes in cellular extracts, suggesting a role in translation. In agreement with this notion, overexpression of LARP4B stimulated protein synthesis, whereas knockdown of the factor by RNA interference impaired translation of a large number of cellular mRNAs. LARP4B as a stimulatory factor of translation. LARP4B exerts its function by bridging mRNA factors of the 3′ end with initiating ribosomes.