Activation loop phosphorylation of a protein kinase is a molecular marker of organelle size that dynamically reports flagellar length

• DOI: 10.1073/pnas.1302364110
• Publication Date: 2013-07-09T02:49:24Z
• Authors: Muqing Cao; Dan Meng; Liang Wang; Shuqing Bei; William J. Snell; Junmin Pan
• Keywords: Organelle; Chlamydomonas

Specification of organelle size is crucial for cell function, yet we know little about the molecular mechanisms that report and regulate growth steady-state dimensions. The biflagellated green alga Chlamydomonas requires continuous-length feedback to integrate multiple events support flagellar assembly disassembly at same time maintain sensory motility functions organelle. Although several length mutants have been characterized, requisite reporter has not identified. Previously, showed depletion aurora-like protein kinase CALK inhibited a gel-shift–associated phosphorylation marked half-length flagella during assembly. Here, show on T193, consensus site activation loop required activity, distinct from triggered when shortening induced, thereby implicating activity in arm control. Moreover, T193 dynamically related length. It reduced cells with short flagella, elevated long mutant, lf4, tracks both WT, but lf4 . Thus, its implicated mechanism continuous dynamic marker disassembly.