Microtubule-associated protein that mediates aggregation of mitochondria resulting in cell death and genomic destruction (MAGD). Plays a role in anchoring the microtubule organizing center to the centrosomes. Binds to DNA. Plays a role in apoptosis (By similarity). Involved in the formation of microtubule bundles. Heterodimer of a heavy and a light chain. Interacts with microtubules and actin. Both MAP1S heavy and light chains interact with microtubules. MAP1S light chain interacts with actin. Interacts with ESR1, LRPPRC, RASSF1, microtubules and VCY2. Interacts with WDR47 (via N-terminus of light chain) (By similarity). Interacts (via C-terminus) with GAN (via Kelch domains). Detected in perinuclear punctate network corresponding to mitochondrial aggregates and in the nucleus in cells exhibiting apoptosis. Associated specifically with microtubules stabilized by paclitaxel and colocalizes with RASSF1. In interphase cells, shows a diffuse cytoplasmic staining with partial localization to the microtubules. During the different stages of mitosis detected at the spindle microtubules. Detected in filopodia-like protrusions and synapses (By similarity). Expressed in ventral and dorsal horns of the spinal cord, hippocampus, cerebral cortex, molecular, Purkinje and granular cell layers of the cerebellum and in dorsal root ganglia of the PNS (at protein level). Expressed in brain, testis, heart, lung, kidney and liver. Expressed in embryo at 10 dpc onwards (at protein level). Its C-terminal part of the heavy chain interacts with ESR1 (By similarity). The N-terminus of the heavy chain associates with the C-terminus of the light chain to form the heterodimer complex. Belongs to the MAP1 family. Contaminating sequence. At the N-terminus.