Regulates phosphorylation of a number of proteins involved in translation regulation including EIF2A, EIF4EBP1 and RPS6KB1. May be involved in the endoplasmic reticulum stress response. By endoplasmic reticulum stress-inducing agents such as tunicamycin and thapsigargin in liver, kidney and cerebrum. No obvious phenotypic abnormalities but mice show increased phosphorylation of Eif2a and decreased phosphorylation of Eif4ebp1 and Rps6kb1. 'Niban' means 'second' in Japanese. Belongs to the Niban family. Contaminating sequence. Potential poly-A sequence. Truncated N-terminus. Truncated N-terminus. Truncated N-terminus. Intron retention.