TNNI1

Protein identityUniProt · HPA

UniProt accession

P19237

Gene

TNNI1

Ensembl

ENSG00000159173

Chromosome

1

Canonical length

187 aa

Protein class

Predicted intracellular proteins

Subcellular location

Nucleoplasm,Nucleoli

OverviewNCBI Gene

Troponin proteins associate with tropomyosin and regulate the calcium sensitivity of the myofibril contractile apparatus of striated muscles. Troponin I (TnI), along with troponin T (TnT) and troponin C (TnC), is one of 3 subunits that form the troponin complex of the thin filaments of striated muscle. TnI is the inhibitory subunit; blocking actin-myosin interactions and thereby mediating striated muscle relaxation. The TnI subfamily contains three genes: TnI-skeletal-fast-twitch, TnI-skeletal-slow-twitch, and TnI-cardiac. The TnI-fast and TnI-slow genes are expressed in fast-twitch and slow-twitch skeletal muscle fibers, respectively, while the TnI-cardiac gene is expressed exclusively in cardiac muscle tissue. This gene encodes the Troponin-I-skeletal-slow-twitch protein. This gene is expressed in cardiac and skeletal muscle during early development but is restricted to slow-twitch skeletal muscle fibers in adults. The encoded protein prevents muscle contraction by inhibiting calcium-mediated conformational changes in actin-myosin complexes. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

187 residues, UniProt reviewed canonical sequence.

>P19237|TNNI1
     1  MPEVERKPKI TASRKLLLKS LMLAKAKECW EQEHEEREAE KVRYLAERIP TLQTRGLSLS
    61  ALQDLCRELH AKVEVVDEER YDIEAKCLHN TREIKDLKLK VMDLRGKFKR PPLRRVRVSA
   121  DAMLRALLGS KHKVSMDLRA NLKSVKKEDT EKERPVEVGD WRKNVEAMSG MEGRKKMFDA
   181  AKSPTSQ

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against TNNI1 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability

Intracellular

Secreted

No

Transmembrane segments

0

Mean surface accessibility (rSASA)

0.57

Highest tissue expression

11,781 nTPM

Expression across tissuesHPA

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)

1.2

gnomAD pLI

0

gnomAD missense Z

1.65

DepMap mean gene effect

-0.1

DepMap dependency class

selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

• cardiac muscle contraction
• regulation of striated muscle contraction
• skeletal muscle contraction
• transition between fast and slow fiber
• ventricular cardiac muscle tissue morphogenesis

Molecular functions

• actin binding

Cellular components

• cytosol
• troponin complex

Protein domainsUniProt · Pfam · InterPro

• Troponin
• Troponin domain superfamily
• Troponin I
• Troponin

KeywordsUniProt

• Acetylation
• Actin-binding
• Muscle protein
• Phosphoprotein

InteractionsUniProt · HPA

Protein binding partners of TNNI1 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

• TNNC1