There are other different nonconventional mechanisms and precedents for moving prorins directly across membranes A number of proteins, e.g. FGF, IL-1 synthesized on free ribosomes in the cytosol, arrive at the cell surface without ever entering the classical secretory pathway. And as above mentioned the directly transport of some proteins into lysosomes for degration. It is possible that there are some private transport pumps, by which a subset of small specific proteins are transfered specialy across a particular membrane such as the ABC transporter family, e.g. a small yeast peptide the pheromone a-factor is mediated directly across the plasma membrane into outside of cells. There is also other possibility that some proteins with a certain specific sequence may transfer directly across the membranes, such as HIV-1 TAT protein(86 aa) with of specific sequence(48 to 60) contains a cluster of eight basic amino acids within a nine residues of line sequence(-RKKRRQRRR-), is able to translocate efficientlyThere are other different nonconventional mechanisms and precedents for moving prorins directly across membranes. A number of proteins, e.g. FGF, IL-1 synthesized on free ribosomes in the cytosol, arrive at the cell surface without ever entering the classical secretory pathway. And as above mentioned the directly transport of some proteins into lysosomes for degration. It is possible that there are some “private” transport pumps, by which a subset of small specific proteins are transfered specialy across a particular membrane, such as the ABC transporter family, e.g. a small yeast peptide, the pheromone a-factor is mediated directly across the plasma membrane into outside of cells. There is also other possibility that some proteins with a certain specific sequence may transfer directly across the membranes, such as HIV-1 TAT protein (86 aa) with of specific sequence (48 to 60) contains a cluster of eight basic amino acids within a nine residues of line sequence (-RKKRRQRRR-), is able to translocate efficiently