CALMODULIN (CaM -Short Note)

CALMODULIN(CaM)

INTRODUCTION:

Calmodulin (CaM) (an abbreviation for CALcium-MODULated proteIN). 

It is a calcium-binding messenger protein expressed in all eukaryotic cells.

Calmodulin

STRUCTURE:

SIZE: Small protein approximately 148 amino acid long.

SHAPE: Dumb bell shaped protein with its N and C terminals domains joined by a central helix.

Ca Binding sites:  Total four sites with  each domain having two high affinity calcium binding sites.

Binding of calcium to these sites causes conformational changes in calmodulin and it binds tightly to the target protein.

Structural change in calmodulin makes it encase the target protein tightly

FUNCTIONS:

CaM mediates many crucial processes such as

• inflammation 
• metabolism
• apoptosis
• smooth muscle contraction
• intracellular movement
• short-term and long-term memory
• immune response
• Abundantly found in Enamel and plays an important role in binding calcium.

ADDITIONAL INFORMATION:

some important enzymes activated by binding of Ca to calmodulin are

1.  adenyl cyclase- conversion of ATP- AMP
2.  Calcium dependent protein kinases : many signaling cascades and is thought to be an important mediator of learning and memory, Immune signaling
3. Ca Mg ATPase : regulating the amount of Ca2+ within cells
4. Glycogen synthase- is an enzyme involved in converting glucose to glycogen
5. Myosin Kinase: important in the contraction in muscle
6. Phospholipase-C- enzymes that cleave phospholipids- important in signal transduction.
7. Pyruvate dehydrogenase: transforming pyruvate into acetyl-CoA.