Schizophrenia-associated Mitotic Arrest Deficient-1 (MAD1) regulates the polarity of migrating neurons in the developing neocortex
Bon Seong Goo, Dong Jin Mun, Seunghyun Kim, Truong Thi My Nhung, Su Been Lee, Young Sik Woo, Soo Jeong Kim, Bo Kyoung Suh, Sung Jin Park, Hee-Eun Lee, Kunyou Park, Hyunsoo Jang, Jong‐Cheol Rah, Ki‐Jun Yoon, Seung Tae Baek, Seung‐Yeol Park, Sang Ki Park, Seung‐Yeol Park, Sang Ki Park, Sang Ki Park
Abstract
Although large-scale genome-wide association studies (GWAS) have identified an association between MAD1L1 (Mitotic Arrest Deficient-1 Like 1) and the pathology of schizophrenia, the molecular mechanisms underlying this association remain unclear. In the present study, we aimed to address these mechanisms by examining the role of MAD1 (the gene product of MAD1L1) in key neurodevelopmental processes in mice and human organoids. Our findings indicated that MAD1 is highly expressed during active cortical development and that MAD1 deficiency leads to impairments in neuronal migration and neurite outgrowth. We also observed that MAD1 is localized to the Golgi apparatus and regulates vesicular trafficking from the Golgi apparatus to the plasma membrane, which is required for the growth and polarity of migrating neurons. In this process, MAD1 physically interacts and collaborates with the kinesin-like protein KIFC3 (kinesin family member C3) to regulate the morphology of the Golgi apparatus and neuronal polarity, thereby ensuring proper neuronal migration and differentiation. Consequently, our findings indicate that MAD1 is an essential regulator of neuronal development and that alterations in MAD1 may underlie schizophrenia pathobiology.