'Tired' Grillo overhauls leadership of Italy's 5-Star Movement ROME (Reuters) - Beppe Grillo, the unruly comic who built Italy's 5-Star Movement into one of the most potent anti-establishment forces in Europe, is struggling to stop a steady slide following months of infighting and electoral setbacks. After a week that saw two local election defeats and two parliamentary members expelled from the party, Grillo announced his movement needed a more formal leadership structure. A five-member committee, approved by an online poll, will take over much day-to-day running with the aim of strengthening foundations for the future. The 66-year-old Grillo said he would remain as "guarantor" but what that means is unclear. "I'm pretty tired, as Forrest Gump would say," he wrote in his blog beneath a mock-up of himself as the movie character, telling a band of followers that he is ending a marathon run across the country. One of the most successful of the anti-system parties that have blossomed in Europe during the financial crisis, Grillo's movement is fueled by anger at a corrupt and inefficient political class. It remains Italy's second-biggest party but after its triumph in the 2013 elections, when it won 25 percent of the vote, it has struggled in parliament. In the latest of a string of disputes over issues including whether members may appear on television, two deputies were thrown out this week, accused of failing to repay state funding as party rules demand. The latest expulsions left the 5-Star Movement with 143 seats in parliament, compared with the 163 it won last year. It has done poorly in recent local elections, taking only 13 percent and 5 percent respectively last week in the regions of Emilia-Romagna and Calabria. In its place, the anti-immigrant Northern League, which shares Grillo's hostility to the euro, is capturing more of the protest vote, coming second in Emilia-Romagna, a traditional stronghold of the left. Even Silvio Berlusconi, fighting to regain influence following a conviction for tax fraud, has re-emerged. In an opinion poll last week, he beat Grillo's personal approval rating for the first time in months. Grillo's tired. I'm in better form than ever," he said on Saturday. Marco Travaglio, a prominent columnist for Il Fatto Quotidiano, a newspaper generally sympathetic to Grillo's movement, wrote that the disputes were "suicidal" and would only strengthen Prime Minister Matteo Renzi, "who, with adversaries like this, can stay 100 years."