A spokesman for Labour leader Sir Keir Starmer said Ms Long-Bailey had been asked to step down this afternoon.
They said: "The article Rebecca shared earlier today contained an antisemitic conspiracy theory. As Leader of the Labour Party, Keir has been clear that restoring trust with the Jewish community is a number one priority.
"Antisemitism takes many different forms and it is important that we all are vigilant against it.”
Ms Long-Bailey shared the article, an interview with actress Maxine Peake, commenting: "Maxine Peake is an absolute diamond."
But in the article Ms Peake had said the police who killed George Floyd in America had learned their techniques from the Israeli secret service.
Israel's police service denied this and said there was no protocol which involved placing pressure on the neck or airways.
In a Twitter thread, Ms Long-Bailey said: "I retweeted an interview that my constituent and stalwart Labour Party supporter Maxine Peake gave to the Independent. It's main thrust was anger with the Conservative Government’s handling of the current emergency and a call for Labour Party unity.
"These are sentiments are shared by everyone in our movement and millions of people in our country. I learned that many people were concerned by references to international sharing of training and restraint techniques between police and security forces.
"In no way was my retweet an intention to endorse every part of that article. I wished to acknowledge these concerns and duly issued a clarification of my retweet, with the wording agreed in advance by the Labour Party Leader’s Office, but after posting I was subsequently instructed to take both this agreed clarification and my original retweet down.
"I could not do this in good conscience without the issuing of a press statement of clarification. I had asked to discuss these matters with Keir before agreeing what further action to take, but sadly he had already made his decision.
"I am proud of the policies we have developed within the party from our Green Industrial Revolution to a National Education Service and I will never stop working for the change our communities need to see.
"I am clear that I shall continue to support the Labour Party in Parliament under Keir Starmer’s leadership, to represent the people of Salford and Eccles and work towards a more equal, peaceful and sustainable world."
Former shadow chancellor John McDonnell tweeted his support for Ms Long-Bailey.
He said: “Throughout discussion of anti-Semitism it’s always been said criticism of practices of Israeli state is not anti-Semitic. I don’t believe therefore that this article is or @RLong_Bailey should’ve been sacked. I stand in solidarity with her.”
But Marie van der Zyl, president of the Board of Deputies of British Jews, has thanked Sir Keir for his “swift action”.
She said: “I would like to thank Keir Starmer for backing his words with actions on anti-Semitism. After Rebecca Long-Bailey shared a conspiracy theory, we and others gave her the opportunity to retract and apologise.
“To our surprise and dismay, her response was pathetic. Her position as shadow education secretary was therefore untenable.
“There can be no space for this sort of action in any party and it is right that after so many challenging years Labour is now making this clear under its new leader.”
And Jonathan Goldstein, chair of the Jewish Leadership Council, said: “Today we saw significant action from Sir Keir Starmer in ensuring there is zero tolerance for anti-Semitism within the Labour Party.
“His actions show he understands the severity and harm that anti-Semitic conspiracies do to our politics. We welcome this decisive leadership and firm action.”
Labour MP Dame Margaret Hodge, who is Jewish, tweeted: “This is what a change in culture looks like. This is what zero tolerance looks like. This is what rebuilding trust with the Jewish community looks like.”
Dame Margaret previously described Sir Keir’s predecessor Jeremy Corbyn as racist following claims he had failed to take strong enough action on anti-Semitism within the party.