Required for both chromosome condensation and segregation and for X-chromosome dosage compensation depending on its binding partners (PubMed:8939869, PubMed:8939870, PubMed:19119011, PubMed:2917714, PubMed:19781752). Member of the condensin I complex, a complex required for conversion of interphase chromatin into mitotic-like condense chromosomes and for proper chromosome segregation in mitosis and meiosis (PubMed:19119011, PubMed:19781752). As a member of the condensin I complex, further controls the crossover number and distribution in meiosis by restricting double strand break formation, probably by influencing higher-order chromosome structure (PubMed:19781752, PubMed:18198337). Plays a role in robust cytokinesis upon presence of chromatin obstructions (PubMed:23684975). Also a member of the condensin I-like dosage compensation complex that associates specifically with hermaphrodite X chromosomes to reduce their gene transcription during interphase, possibly through chromatin reorganization (PubMed:19119011, PubMed:8939870, PubMed:2917714, PubMed:19781752). As a member of the dosage compensation complex, also binds to regulatory regions of the autosomal her-1 gene, required for male development, possibly contributing to its repression in hermaphrodites (PubMed:11937488). Component of the condensin I complex, which contains the mix-1/SMC2 and smc-4/SMC4 heterodimer, and three non SMC subunits that probably regulate the complex: dpy-26, capg-1 and dpy-28 (PubMed:19119011, PubMed:19781752). Within the complex, interacts with dpy-28, mix-1, smc-4 and capg-1 (PubMed:15557118, PubMed:18198337, PubMed:19781752, PubMed:19119011, PubMed:28301465). Component of the dosage compensation complex, which consists of the condensin I-like components mix-1/SMC2 and dpy-27/SMC4, and the three non SMC subunits dpy-26, capg-1 and dpy-28 (PubMed:19119011, PubMed:19781752). Within the complex, interacts with dpy-27, dpy-28, mix-1 and capg-1 (PubMed:8939870, PubMed:15557118, PubMed:18198337, PubMed:19781752, PubMed:19119011, PubMed:9458050, PubMed:28301465). The interaction with dpy-27 is required for dpy-27 protein stability (PubMed:8939870). Interacts with smcl-1 (PubMed:28301465). During meiosis and mitosis, localizes to condensed chromosomes (PubMed:8939869). In interphase cells, diffusely distributed in nuclei of hermaphrodite embryos prior to the onset of dosage compensation (PubMed:8939869). Localizes to the X chromosome after the 40-cell stage when dosage compensation is initiated in hermaphrodite (XX) but not in male (X0) embryos, where it remains diffusely nuclear (PubMed:8939869, PubMed:18198337). Expressed in embryos and in somatic and germline tissues in L4 stage larvae (at protein level). Results in larval lethality in XX hermaphrodites; survivors exhibit shorter and stouter body morphology and are egg-laying defective (PubMed:2917714). Male animals are viable (PubMed:2917714). Higher percentage of spontaneous males through X chromosome non-disjunction (PubMed:2917714). Disrupts protein stability of dpy-27 (PubMed:8939870). Disrupts localization of dpy-28 and of capg-1 to the hermaphrodite X-chromosome (PubMed:18198337, PubMed:19119011). RNAi-mediated knockdown results in chromosome segregation defects in mitosis and meiosis (PubMed:19119011). In a sex-1 mutant background, leads to high embryonic lethality (PubMed:19119011).