Figure 4.

Mitochondrial fusion is modulated by cytosol and phosphorylated proteins. (a) Replacing cytosol with 3 mg/mL bovine serum albumin or 0.3 - 3 mg/mL placental or HeLa cytosol demonstrates a differential modulation of the fusion reaction depending upon the source. (b) Addition of 1, 0.1 and 0.001 units of shrimp intestinal phosphatase (SIP) show an absolute requirement for phosphorylated proteins in the fusion reaction. Heat inactivated SIP did not inhibit the reaction.