Meneghetti Maria C Z, Cavalheiro Renan P, Yates Edwin A, Nader Helena B, Lima Marcelo A
Departamento de Bioquímica, Instituto de Farmacologia e Biologia Molecular, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil.
Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, UK.
FEBS J. 2025 May;292(9):2237-2250. doi: 10.1111/febs.17398. Epub 2025 Jan 13.
Vesicle trafficking is pivotal in heparan sulfate (HS) biosynthesis, influencing its spatial and temporal regulation within distinct Golgi compartments. This regulation modulates the sulfation pattern of HS, which is crucial for governing various biological processes. Here, we investigate the effects of silencing Rab1A and Rab2A expression on the localisation of 3-O-sulfotransferase-5 (3OST5) within Golgi compartments and subsequent alterations in HS structure and levels. Interestingly, silencing Rab1A led to a shift in 3OST5 localization towards the trans-Golgi, resulting in increased HS levels within 24 and 48 h, while silencing Rab2A caused 3OST5 accumulation in the cis-Golgi, with a delayed rise in HS content observed after 48 h. Furthermore, a compensatory mechanism was evident in Rab2A-silenced cells, where increased Rab1A protein expression was detected. This suggests a dynamic interplay between Rab1A and Rab2A in maintaining the fine balance of vesicle trafficking processes involved in HS biosynthesis. Additionally, we demonstrate that the trafficking of 3OST5 in COPI vesicles is facilitated by GOLPH3 protein. These findings identify novel vesicular transport mechanisms regulating HS biosynthesis and reveal a compensatory relationship between Rab1A and Rab2A in maintaining baseline HS production.
囊泡运输在硫酸乙酰肝素（HS）生物合成中起关键作用，影响其在不同高尔基体区室中的空间和时间调节。这种调节会改变HS的硫酸化模式，而硫酸化模式对于控制各种生物过程至关重要。在此，我们研究沉默Rab1A和Rab2A表达对3-O-磺基转移酶-5（3OST5）在高尔基体区室中的定位以及随后HS结构和水平变化的影响。有趣的是，沉默Rab1A导致3OST5定位向反式高尔基体转移，导致24小时和48小时内HS水平升高，而沉默Rab2A导致3OST5在顺式高尔基体中积累，48小时后观察到HS含量延迟上升。此外，在Rab2A沉默的细胞中明显存在一种补偿机制，其中检测到Rab1A蛋白表达增加。这表明Rab1A和Rab2A之间在维持HS生物合成中涉及的囊泡运输过程的精细平衡方面存在动态相互作用。此外，我们证明GOLPH3蛋白促进了3OST5在COPI囊泡中的运输。这些发现确定了调节HS生物合成的新型囊泡运输机制，并揭示了Rab1A和Rab2A在维持基线HS产生方面的补偿关系。
