Protein kinase N1 (PKN1), a serine/threonine kinase, has been shown to play crucial roles in multiple biological processes. It contributes to Glut4 translocation and glucose transport, regulating adipocyte differentiation and glucose metabolism [1]. PKN1 is also involved in the regulation of synaptic maturation in the brain, and its functions are associated with pathways like AKT and the regulation of transcription factors such as NeuroD2 [2,3].

Pkn1 knockout mouse models have revealed significant insights. In the hippocampus, Pkn1 knockout led to elevated phospho-AKT and NeuroD2 levels, enhancing the expression of the AMPAR subunit GluA1, which may be related to neurological disorders [2]. In an in vitro model of cerebellar hypoxic-ischemic encephalopathy, Pkn1 knockout in cerebellar granule cells showed higher AKT phosphorylation, reduced caspase-3 activation, and improved survival, indicating a neurodegenerative role of PKN1 [3]. In retinal cell type formation, Pkn1 knockout led to changes in the number of certain cell types, suggesting its importance in retinal development [4]. In mouse embryonic fibroblasts, PKN1 kinase-deficient cells showed delayed aggregate formation and abnormal spheroid compaction [5]. In aged PKN1 kinase-negative knock-in mice, there was splenomegaly and leukopenia without obvious autoimmune-like phenotypes, highlighting potential kinase-independent functions of PKN1 [6].

In conclusion, PKN1 is a key regulator in various biological processes, including adipocyte function, synaptic maturation, and cell survival in the nervous system. The use of Pkn1 knockout and kinase-negative knock-in mouse models has provided valuable insights into its roles in diseases such as insulin resistance, neurodegenerative conditions, and potential hematological disorders. These findings may offer new therapeutic approaches for related diseases.