by Séverine Altairac

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Senora Pilasana
Voulez-vous le taximeter?
Le tionta su la seata
Tu la tu la tu la wa

This is gibberish sung by Charlie Chaplin in ‘Modern Times’ as he struggles to satisfy an impatient audience whilst frantically seeking for his cuff – on which he had written the true lyrics – which had flown off his wrist following an unfortunate flick as he made a hasty entry to perform. He ad-libs novel lyrics to the tune of ‘Je cherche après Titine’ (‘Looking for Titine’) a then popular French song written by M.Bertal and L.Maubon in 1917, the music of which was composed by L.Daniderff. As a result, Chaplin not only added to the song’s popularity but also made it worldwide. Little did he know though that what helped him to dash around the dining-room as he searched for the lost cuff is also named…titin….

Humans can dash around thanks to their muscles. Titin is the name of a protein which abounds in our muscle cells – in particular, the heart and skeletal muscle cells. It has been named ‘titin’ because amongst proteins, titin is…a titan. On an average, a protein consists of 500 amino acids; titin, however, is 34'350 amino acids long! Which not makes it the longest and no doubt one of the largest proteins in the living world. Its structure is such that it binds to various other muscle proteins and, along with titin, these proteins form a distinct functional unity that contracts and expands with every muscular effort.

Titin is essential. It acts like a spring making sure that the architecture of the functional unity is not lost despite continuous and repetitive contraction and expansion. Consequently, an anomaly in titin – such as amino acid replacements – could affect a muscle and be at the heart of certain myopathies or cardiomyopathies. Fortunately though, such an occurrence is rare.

It was not titin Chaplin was looking for …yet it was titin he had… Although, of little help this knowledge was to the Tramp who never found his cuff!

UniProt cross references
Titin, Homo sapiens (human): Q8WZ42
Protein Spotlight (ISSN 1424-4721) is a monthly review written by the Swiss-Prot team of the SIB Swiss Institute of Bioinformatics. Spotlight articles describe a specific protein or family of proteins on an informal tone. Follow us: Subscribe · Twitter · Facebook