The Hbx5-MybG transcription factor complex enables adaptive changes in macropinocytosis during the growth-to-development transition. Credit: Cai Huaqing’s group

Macropanocytosis is one of the major pathways by which cells nonselectively internalize extracellular fluids. The laboratory strain Dictyostelium discoideum serves as a valuable model to study the regulation of macropinocytosis.

This model cell is a social amoeba that exists as a When nutrients are abundant and use macropinocytosis to acquire nutrients. Under conditions of nutritional deficiency, it enters a and undergoes directed migration to form multicellular structures. gave The reason behind this transition from macropinocytosis to transition mode is still unclear.

In one study published I Developmental cells On February 6, researchers led by Professor Kai Huaqing of the Institute of Biophysics of the Chinese Academy of Sciences, together with Professor Li Li of Peking University, revealed the molecular mechanisms by which cells undergo macropinocytosis in response to nutrients. regulate the level of Stress

Further through genetic screening and researchers first identified two transcription factors, Hbx5 and MybG, that are involved in macropinocytosis.

Using microscopy, biochemical experiments, RNA-Seq, and ChIP-Seq, the researchers found that Hbx5 and MybG form a heterodimeric complex. During the nutritive growth phase, this complex forms locally. and regulates the expression of genes involved in macropinocytosis, maintaining high levels of macropinocytosis.

Under nutritional stress, oscillatory cAMP signaling causes the Hbx5-MybG complex to undergo nucleocytoplasmic shuttling, resulting in the downregulation of genes involved in macropinocytosis. As the frequency of cAMP oscillatory signaling increases during development, the Hbx5-MybG complex ceases shuttling and becomes trapped in the cytoplasm, turning off the expression of genes promoting macropinocytosis and directed migratory behavior. Makes the transition easier.

This study has identified key regulatory components that enable cells to maintain macropinocytosis and alter its levels in response to nutritional stress. This not only provides new insights into the molecular mechanisms by which cells control macropinocytosis. It also opens new avenues to study the mechanisms of oscillatory signaling in cells.

More information:
Yazhou Hao et al, A transcription factor complex in Dictyostelium enables adaptive changes in macropinocytosis during the developmental-to-developmental transition, Developmental cells (2024). DOI: 10.1016/j.devcel.2024.01.012

Reference: Researchers discover how cells modulate macropinocytic activity (2024, February 21) Retrieved February 21, 2024 from

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