Increasing Tert mRNA expression by blocking leucine zipper sequence with function-blocking RHAMM peptide NP-110 in a TERT-deficient mouse model of idiopathic pulmonary fibrosis, alongside suppressing Tpp1 and Pot1a expression in mouse embryonic fibroblasts using ERK1 inhibitor PD98059, highlights the importance of the HATABD domain (amino acids 718–751), which includes leucine zipper and ERK-binding sequences at the C-terminus of mouse RHAMM in regulating telomerase function. Here, MAPK3 is linked to idiopathic pulmonary fibrosis.