Which motor protein is responsible for P-granule migration?
P-granules, ribonucleoprotein assemblies marking germline, segregate to posterior blastomere P1 during first division and subsequently to germline precursors P2-P4. Their posterior migration along cell cortex before division requires microtubule motor dynein transporting granule components along cortical microtubules toward centrosome at posterior pole. PAR-1 dependent microtubule organization creates flow. Mutants in dynein heavy chain dhc-1 or its regulator dynactin cause equal distribution of P-granules to both AB and P1, losing germline restriction. Myosin II and kinesin contribute to cortical flows but dynein-driven transport is primary driver ensuring germ plasm inheritance by germline lineage.
Ref: Updike & Strome 2010; Gilbert Chapter 4: Dynein motor responsible for P-granule migration in early embryo.