THE ACTIN GELLING ACTIVITY OF CHICKEN GIZZARD ALPHA-ACTININ AT PHYSIOLOGICAL TEMPERATURE IS TRIGGERED BY WATER SEQUESTRATION

At 37°C, in the presence of 6% ( w v) polyethylene glycol 6000, 30 nM α-actinin from chicken gizzard induces the gelation of 12 μM actin. Static measurement shows that the addition of 30 nM α-actinin increases the rigidity of the system from 23.5 to 54 dynes cm2. According to the theory of osmoelastic coupling, also large additives, such as the proteins of the cell sap, are able to cause an osmotic stress equivalent to that caused by polyethylene glycol. We thus conclude that, in vivo, α-actinin acts as an actin gelling protein. © 1990.