Preferential turnover of membrane proteins in the intact Chlamydomonas flagellum.

Radioactive labeling studies demonstrate a continuous incorporation of newly synthesized proteins and glycoproteins into the intact flagella of Chlamydomonas. This apparent turnover is preferentially occurring for membrane components. In particular, two classes of flagellar membrane components, one a high molecular weight (HMW) group of closely migrating glycoproteins and the other a protein with a MW around 65 kD, are continuously turning over in the vegetative cell. This selective protein turnover may explain the ability of Chlamydomonas to rapidly recover from proteolytic modification of the flagellar surface and to change its flagellar surface properties during the early events in mating.