The FDA first approved Invokana as the first SGLT2 drug in March 2013. Since then, it has become a cash cow for J&J and its Janssen Pharmaceuticals unit. In the first quarter of 2015, the drug already brought in $278 million, triple what it made last year.
During contraction, the smooth-muscle cell's intermediate filaments help to draw the cell up, like closing a drawstring purse. Calcium ions regulate contraction in smooth muscle, but they do it in a slightly different way than in skeletal muscle: 1  Calcium ions come from outside of the cell.2  Calcium ions bind to an enzyme complex on myosin, called calmodulin-myosin light chain kinase. Calcium ions come from outside of the cell. 2  Calcium ions bind to an enzyme complex on myosin, called calmodulin-myosin light chain kinase. 3  The enzyme complex breaks up ATP into ADP and transfers the P i directly to myosin. 4  This P i transfer activates myosin.
Calcium and magnesium work together to control muscle contraction. Both minerals interact with the proteins actin and myosin -- structural proteins that shorten with each muscle contraction, then lengthen to relax your muscles.ctin and myosin rely on calcium to shorten and contract your muscles, then rely on magnesium to relax after a contraction. While low calcium levels primarily affect your bones -- causing bone loss and putting you at risk for osteoporosis -- magnesium deficiency affects your muscles, causing abnormal muscle contraction.