troponin-C

Function

• Ca+2-sensing component of troponin complex
• in resting muscle, high affinity Ca+2-binding sites in the C-terminal region (Kd = 0.1 uM) are occupied, but the low affinity ones in the N-terminal regions (Kd = 10 uM) are not
• when Ca+2 is released from the sarcoplasmic reticulum, it occupies the low affinity sites & induces a conformational change that is transmitted though troponin-I & troponin-T to tropomyosin
• Ca+2 controls muscle contraction by an allosteric mechanism in which the flow of information is: Ca+2 -> troponin -> tropomyosin -> actin -> myosin

Structure

• troponin C closely resembles calmodulin

More general terms

• protein subunit
• Ca+2 binding protein

More specific terms

• troponin C, skeletal muscle (TNNC2)
• troponin C, slow skeletal & cardiac muscles; TN-C (TNNC1 TNNC)

Component of

• troponin