UniProt: the universal protein knowledgebase in 2021
Authors:   The UniProt Consortium, Bateman Alex , Martin Maria-Jesus , Orchard Sandra , Magrane Michele , Agivetova Rahat , Ahmad Shadab , Alpi Emanuele , Bowler-Barnett Emily H , Britto Ramona , Bursteinas Borisas , Bye-A-Jee Hema , Coetzee Ray , Cukura Austra , Da Silva Alan , Denny Paul , Dogan Tunca , Ebenezer ThankGod , Fan Jun , Castro Leyla Garcia , Garmiri Penelope , Georghiou George , Gonzales Leonardo , Hatton-Ellis Emma , Hussein Abdulrahman , Ignatchenko Alexandr , Insana Giuseppe , Ishtiaq Rizwan , Jokinen Petteri , Joshi Vishal , Jyothi Dushyanth , Lock Antonia , Lopez Rodrigo , Luciani Aurelien , Luo Jie , Lussi Yvonne , MacDougall Alistair , Madeira Fabio , Mahmoudy Mahdi , Menchi Manuela , Mishra Alok , Moulang Katie , Nightingale Andrew , Oliveira Carla Susana , Pundir Sangya , Qi Guoying , Raj Shriya , Rice Daniel , Lopez Milagros Rodriguez , Saidi Rabie , Sampson Joseph , Sawford Tony , Speretta Elena , Turner Edward , Tyagi Nidhi , Vasudev Preethi , Volynkin Vladimir , Warner Kate , Watkins Xavier , Zaru Rossana , Zellner Hermann , Bridge Alan , Poux Sylvain , Redaschi Nicole , Aimo Lucila , Argoud-Puy Ghislaine , Auchincloss Andrea , Axelsen Kristian , Bansal Parit , Baratin Delphine , Blatter Marie-Claude , Bolleman Jerven , Boutet Emmanuel , Breuza Lionel , Casals-Casas Cristina , de Castro Edouard , Echioukh Kamal Chikh , Coudert Elisabeth , Cuche Beatrice , Doche Mikael , Dornevil Dolnide , Estreicher Anne , Famiglietti Maria Livia , Feuermann Marc , Gasteiger Elisabeth , Gehant Sebastien , Gerritsen Vivienne , Gos Arnaud , Gruaz-Gumowski Nadine , Hinz Ursula , Hulo Chantal , Hyka-Nouspikel Nevila , Jungo Florence , Keller Guillaume , Kerhornou Arnaud , Lara Vicente , Le Mercier Philippe , Lieberherr Damien , Lombardot Thierry , Martin Xavier , Masson Patrick , Morgat Anne , Neto Teresa Batista , Paesano Salvo , Pedruzzi Ivo , Pilbout Sandrine , Pourcel Lucille , Pozzato Monica , Pruess Manuela , Rivoire Catherine , Sigrist Christian , Sonesson Karin , Stutz Andre , Sundaram Shyamala , Tognolli Michael , Verbregue Laure , Wu Cathy H , Arighi Cecilia N , Arminski Leslie , Chen Chuming , Chen Yongxing , Garavelli John S , Huang Hongzhan , Laiho Kati , McGarvey Peter , Natale Darren A , Ross Karen , Vinayaka C R , Wang Qinghua , Wang Yuqi , Yeh Lai-Su , Zhang Jian , Ruch Patrick , Teodoro Douglas 
Published: November 2020

The aim of the UniProt Knowledgebase is to provide users with a comprehensive, high-quality and freely accessible set of protein sequences annotated with functional information. In this article, we describe significant updates that we have made over the last two years to the resource. The number of sequences in UniProtKB has risen to approximately 190 million, despite continued work to reduce sequence redundancy at the proteome level. We have adopted new methods of assessing proteome completeness and quality. We continue to extract detailed annotations from the literature to add to reviewed entries and supplement these in unreviewed entries with annotations provided by automated systems such as the newly implemented Association-Rule-Based Annotator (ARBA). We have developed a credit-based publication submission interface to allow the community to contribute publications and annotations to UniProt entries. We describe how UniProtKB responded to the COVID-19 pandemic through expert curation of relevant entries that were rapidly made available to the research community through a dedicated portal. UniProt resources are available under a CC-BY (4.0) license via the web at https://www.uniprot.org/.