Nebulette is an isoform

Protein isoform

A protein isoform is any of several different forms of the same protein. Different forms of a protein may be produced from related genes, or may arise from the same gene by alternative splicing. A large number of isoforms are caused by single-nucleotide polymorphisms or SNPs, small genetic...

 of the protein nebulin

Nebulin

Nebulin is an actin-binding protein which is localized to the I-band of the sarcomeres in skeletal muscle. It is a very large protein and binds as many as 200 actin monomers. Because its length is proportional to thin filament length, it is believed that nebulin acts as a thin filament "ruler"...

. While nebulin (600-900 kDa) is expressed preferentially in skeletal muscle

Skeletal muscle

Skeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system- i.e. it is voluntarily controlled. It is one of three major muscle types, the others being cardiac and smooth muscle...

, nebulette (107 kDa) is expressed in cardiac muscle

Cardiac muscle

Cardiac muscle is a type of involuntary striated muscle found in the walls and histologic foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle...

. Nebulette was identified in 1995 by Moncman and Wang using primary cultures of chicken embryonic cardiomyocytes by immunoprecipitation

Immunoprecipitation

Immunoprecipitation is the technique of precipitating a protein antigen out of solution using an antibody that specifically binds to that particular protein. This process can be used to isolate and concentrate a particular protein from a sample containing many thousands of different proteins...

s with certain anti-nebulin monoclonal antibodies

Monoclonal antibodies

Monoclonal antibodies are monospecific antibodies that are the same because they are made by identical immune cells that are all clones of a unique parent cell....

. Normal expression of nebulette is essential for the assembly and contractile function

Muscle contraction

Muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. While under tension, the muscle may lengthen, shorten, or remain the same...

 of myofibril

Myofibril

A myofibril is a basic unit of a muscle. Muscles are composed of tubular cells called myocytes or myofibers. Myofibers are composed of tubular myofibrils. Myofibrils are composed of long proteins such as actin, myosin, and titin, and other proteins that hold them together...

s.