Carboxylate clamp type tetratricopeptide repeat protein that may act as a potential Hsp90/Hsp70 co-chaperone (PubMed:20856808). Contributes to polar growth of root hairs (PubMed:28096376). Interacts with myosin XI-1 and XI-K. No clumped-chloroplasts phenotype (PubMed:22025705). 31% reduction in root hair growth (PubMed:28096376). Phox1 and phox4 double mutants show no clumped-chloroplasts phenotype, but a 46% reduction in root hair growth (PubMed:22025705, PubMed:28096376). Phox1, phox3 and phox4 triple mutants and phox1, phox2, phox3 and phox4 quadruple mutants show a 70% reduction in root hair growth (PubMed:28096376).