Sarcolipin (SLN) is a 3 kD membrane protein found in sarcoplasmic reticulum 
(SR). It has 31 amino acid residues; SLN and phopholamban (PLB) are belong to 
the same protein family, so they have similar physiological functions. SLN 
inhibits sarcoplasmic reticulum Ca(2+) ATPase (SERCA) activity and reduces its 
affinity of Ca(2+), resulting in dysfunction of myocardial contraction and heart 
failure. However, much remains to be elucidated. SLN independently or in 
conjunction with PLB affects SERCA activity, imbalancing intracellular calcium 
homeostasis, and reducing myocardial contractivity; these effects promote the 
development of heart failure.