Labour MP Lloyd Russell-Moyle has stepped down from his role as a shadow environment minister, blaming a “campaign by the right-wing media”.
The Brighton Kemptown MP said this had “unleashed a torrent of online hate” and daily abusive calls to his staff.
He said he would need “a few weeks” to recover from stress and support his team.
Mr Russell-Moyle has recently apologised for comments he made about Harry Potter author JK Rowling.
The MP said he had informed Labour leader Sir Keir Starmer of his decision to quit his post after speaking to him on the phone on Thursday.
In a statement on Twitter, he said he said he had made the decision “with regret”, adding media attacks had made it “untenable” for him to stay on.
“It is my job to get political flak, but it is not the job of caseworkers, researchers and assistants to be attacked,” he added.
“I remain incredibly proud of the work I have done in Parliament in the past three years”.
He said that he intended to stay on as an MP.
A Labour spokesperson said: “Lloyd spoke to Keir Starmer this afternoon and informed Keir of his decision to step back from front bench duties as shadow minister for the natural environment.
“Keir thanked Lloyd for his hard work on the frontbench and wished him well in his plans for the coming months to focus on housing and youth services.”
Mr Russell-Moyle, who became an MP at the 2017 election, was a prominent supporter of former Labour leader Jeremy Corbyn.
His apology to JK Rowling came after he suggested the writer had used her experience of sexual assault as “justification” for discriminating against transgender people.
He has also said sorry for online comments made before he became an MP, which were reported in the Sunday Times.
He apologised for the comments, suggesting Jewish claims to Israel were “not progressive in [their] very nature” and that Zionism was a “dangerous nationalist idea”, which he said he recognised as “offensive”.
In December 2018 he caused controversy by removing the ceremonial mace in the House of Commons during a Brexit debate as a “symbolic stunt”.