Exposing T Cell Secrets Inside and Outside the Thymus

The many faces of the zinc finger protein 335 in brain development and immune system

Zinc finger protein 335 (ZNF335) plays a crucial role in the methylation and, consequently, regulates the expression of a specific set of genes. Variants of the ZNF335 gene have been identified as risk factors for microcephaly in a variety of populations worldwide. Meanwhile, ZNF335 has also been identified as an essential regulator of T-cell development. However, an in-depth understanding of the role of ZNF335 in brain development and T cell maturation is still lacking. In this review, we summarize current knowledge of the molecular mechanisms underlying the involvement of ZNF335 in neuronal and T cell development across a wide range of pre-clinical, post-mortem, ex vivo, in vivo, and clinical studies. We also review the current limitations regarding the study of the pathophysiological functions of ZNF335. Finally, we hypothesize a potential role for ZNF335 in brain disorders and discuss the rationale of targeting ZNF335 as a therapeutic strategy for preventing brain disorders.

Protein ubiquitination in T cell development

As an important form of posttranslational modification, protein ubiquitination regulates a wide variety of biological processes, including different aspects of T cell development and differentiation. During T cell development, thymic seeding progenitor cells (TSPs) in the thymus undergo multistep maturation programs and checkpoints, which are critical to build a functional and tolerant immune system. Currently, a tremendous amount of research has focused on the transcriptional regulation of thymocyte development. However, in the past few years, compelling evidence has revealed that the ubiquitination system also plays a crucial role in the regulation of thymocyte developmental programs. In this review, we summarize recent findings on the molecular mechanisms and cellular pathways that regulate thymocyte ubiquitination and discuss the roles of E3 ligases and deubiquitinating enzymes (DUBs) involved in these processes. Understanding how T cell development is regulated by ubiquitination and deubiquitination will not only enhance our understanding of cell fate determination via gene regulatory networks but also provide potential novel therapeutic strategies for treating autoimmune diseases and cancer.