MRPL42 is a mitochondrial ribosomal protein component of the large ribosomal subunit that functions in mitochondrial translation 1. As a structural constituent of the mitochondrial ribosome, MRPL42 is essential for synthesizing mitochondrial proteins and maintaining oxidative phosphorylation (OXPHOS) capacity 2. The protein localizes to the mitochondrial inner membrane and participates in ribosomal RNA binding during translation [GO annotations]. MRPL42 demonstrates significant disease relevance across multiple contexts: it is upregulated in glioma tissues and functions as an oncogene promoting cell proliferation, with MRPL42 knockdown inducing G1/G2/M cell cycle arrest and apoptosis in glioma cells 1. Similarly, MRPL42 is overexpressed in hepatocellular carcinoma, where it supports malignant progression through OXPHOS regulation; knockdown impairs ATP production and mitochondrial respiratory function 2. In neuropsychiatric contexts, MRPL42 dysregulation associates with depression pathology, and its restoration by antidepressant compounds correlates with improved mitochondrial and synaptic homeostasis 345. MRPL42 also appears in immune-related networks, including EBV-host interactions and severe asthma immune dysregulation 67. Clinically, MRPL42 emerges as a potential biomarker for cancer diagnosis and prognosis, with therapeutic targeting showing promise for glioma and hepatocellular carcinoma management.