Some of Scotland's best-known artists are backing a campaign to reinstate the late licence at Glasgow's Arches venue.
Glasgow Licensing Board imposed a midnight closure amid police complaints about drug and alcohol incidents.
More than 400 cultural figures - including Makar Liz Lochhead, novelist Irvine Welsh and members of Mogwai, Belle & Sebastian and Franz Ferdinand - signed a letter criticising the move.
An online petition to bring back the licence has attracted 36,000 names.
Last month police made a bid to have the club closed after a woman was found unconscious and officers recorded 26 drug and alcohol-related incidents.
The move was rejected after a lawyer for The Arches argued this was inappropriate.
However, last week the licensing board varied the licence, which means the venue could no longer stay open until 03:00 and must close by midnight.
An online petition was launched which claimed this would endanger the city's arts scene and economy as the nightclub effectively subsidised many of the Arches' other arts-related activities.
The petition also accused the police of "harassment".
Now a letter signed by more than 400 Scottish artists and "creative voices" aims to raise the profile of the campaign.
Addressed to Culture Secretary Fiona Hyslop, Creative Scotland chief executive Janet Archer and Bridget McConnell, chief executive of cultural body, Glasgow Life, the letter expresses "shock and dismay" at the licensing board's decision.
While the letter acknowledges "concerns around safety and drug use" it questions whether the early closure would effectively deal with these and highlights "a needless loss of jobs".
It states: "However, our main concern is that we are not satisfied that full consideration has been given to the potentially catastrophic impact this decision will have on the cultural life of Scotland.
"The Arches nightclub is a powerhouse of the electronic music scene. It has nurtured home-grown acts who have gone on to achieve international renown.
"It has consistently been voted one of the top UK dance venues over the last decade. Thousands of people from all over the country come together at the Arches at weekends, and it is widely regarded by leading professionals as one of the best venues in the world."
The letter also states that the nightclub "plays a vital role in the live music scene" and "helps to fund the Arches theatre and arts venue".
"It is a vital first step for many new artists at the start of their careers," the letter states.
"It is a platform for experimental work that would otherwise be marginalised, and it is the most important year-round home for international contemporary performance in Glasgow.
"As a key venue at the centre of Glasgow's remarkable cultural renaissance of the past 25 years, The Arches' importance to the future of the cultural life of Scotland cannot be overstated, and yet this latest decision leaves it in an extremely compromised situation, the cultural ramifications of which are huge."
The letter ends by asking: "As people responsible for looking after culture and the arts in Scotland and in Glasgow, we ask you to consider what support you can give the Arches board, directors, and staff at this time, and to do all that you can in your power to ensure the continued existence of this vitally important venue."
Last year, the Arches announced it was raising its minimum age for admission to 21 after the suspected drug-related death of a teenage girl who fell ill at the venue. The over-18s policy was later reinstated.
Regane MacColl, 17, died after becoming ill at the club in February 2014. Police linked her death to an ecstasy-like "Mortal Kombat" tablet.
Ch Insp Mark Sutherland, area commander in Glasgow city centre, said police had "acted to protect and ensure public safety" by pursuing a review of the venue's licence.
"In general terms I would emphasise that all licensed premises have a duty to report any incidents of criminality that occur on their premises to the police and this is exactly what I expect and what I believe we receive from our pubs and clubs across the city," he said.
"It is my firm view that the frequency and volume of incidents that were occurring at the Arches nightclub would have resulted in fatal consequences had we not acted.
"As the area commander for Glasgow city centre, I want to see a vibrant city that welcomes and supports artistic talent but this can absolutely not be at a cost to public safety, particularly young people who may be risking their lives week after week."